organic compounds
Methyl α-L-rhamnosyl-(1→2)[α-L-rhamnosyl-(1→3)]-α-L-rhamnoside pentahydrate: synchrotron study
aDepartment of Material and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden, and bDepartment of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
*Correspondence e-mail: lars.eriksson@mmk.su.se
The title hydrate, C19H34O13·5H2O, contains a vicinally disubstituted trisaccharide in which the two terminal rhamnosyl sugar groups are positioned adjacent to each other. The conformation of the trisaccharide is described by the glycosidic torsion angles φ2 = 48 (1)°, ψ2 = −29 (1)°, φ3 = 44 (1)° and ψ3 = 4 (1)°, whereas the ψ2 torsion angle represents a conformation from the major state in solution, the ψ3 torsion angle conformation may have been caught near a saddle-point when compared to its solution structure, in which at least two but probably three conformational states are populated. Extensive intermolecular O—H⋯O hydrogen bonding is present in the crystal and a water-containing channel is formed along the b-axis direction.
Related literature
For a description of L-rhamnose as part of see: Marie et al. (1998); Perry & MacLean (2000). For a description of the conformational dynamics of the title trisaccharide, see: Eklund et al. (2005); Jonsson et al. (2011). For a description of the puckering analysis of the residues, see: Cremer & Pople (1975). For further background to L-rhamnose, see: Ansaruzzaman et al. (1996); Varki et al. (1999); Kulber-Kielb et al. (2007); Lindberg (1998); Säwén et al. (2010).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 1997); cell SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536812027390/hb6841sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812027390/hb6841Isup2.hkl
The synthesis of (I) was described by Eklund et al. (2005) in which all three rhamnosyl residues have the L
The trisaccharide was crystallized at ambient temperature by slow evaporation from a mixture of water and ethanol (1:1). The crystal was mounted in a capillary tube and diffraction data were collected at 100 K on beamline I711 at the Swedish synchrotron radiation facility, MAXLAB, Lund.All hydrogen atoms, except those on the water molecules, were geometrically placed and constrained to ride on the parent atom. The C—H bond distances are 0.98 Å for CH3, 0.99 Å for CH2, 1.00 Å for CH. The O—H bond distance is 0.84 Å for OH groups. The Uiso(H) = 1.5 Ueq(C,O) for the CH3 and OH while it was set to 1.2 Ueq(C) for all other H atoms. Due to the abscence of significant anomalous scatterers, the value of the
was not meaningful, thus the 3220 Friedel equivalents were included in the merging process (MERG 4 in SHELXL). The of each sugar residue is known from the starting compounds used in the synthesis. The hydrogen atoms of the water molecule were located from difference density map, given Uiso(H) = 1.5Ueq(O) and in the the d(O—H) and d(H..H) were restrained to retain the previously known geometry of the water molecule. The H502 is an hydrogen atom connected to a solvent water molecule where the H502 related by a 2 fold axis will be positioned at a much too close distance. The water molecule defined by OW5, H501 and H502 do not strictly fulfil the of the rest of the strucutre, at least this is true for one of the H atoms for this very water molecule.In carbohydrate structures from humans the number of different
is quite limited; typically seven different sugars are present in and (Varki et al., 1999). Constituents of in man add a few more to the repertoire. In bacteria, however, more than 100 different monosaccharide components have been found (Lindberg, 1998). One of them, L-rhamnose (6-deoxy-L-mannose) is present as a major constituent of the O-antigen from Shigella flexneri (Kulber-Kielb et al., 2007) and is the sole monosaccharide in the repeating unit of an O-antigen from a Klebsiella pneumoniae strain (Ansaruzzaman et al., 1996). L-rhamnose is also found a the branch point sugar in some e.g., from Escherichia coli O139 (Marie et al., 1998) and Yersinia enterocolitica serotype O:28 (Perry & MacLean, 2000).In the title compound (I) the three sugar components are all L-rhamnose residues having the α-anomeric configuration. The O-methyl residue (a) is vicinally disubstituted at O2 (residue b) and O3 (residue c) which leads to spatial proximity of also the two latter rhamnosyl groups. The major in trisaccharide (I) are present at the (1 → 2)- and (1 → 3)-linkages, i.e., between residues b and a as well as between residues c and a, respectively. The torsion angles are given by φ2 = 48°, ψ2 = -29°, φ3 = 44° and ψ3 = 4°. In a recent NMR and (MD) simulation study of (I) in water solution <φ> ≈ 40°, when the exo-anomeric conformation was populated, but non-exo conformations with φ < 0° were also significantly populated (Eklund et al., 2005). The dynamics of the ψ torsion angles were found to be highly correlated with both ψ2 and ψ3 being either > 0° or < 0°. The conformation of the X-ray structure (Figure 1) is reminiscent of the conformational states found from the MD simulation and the values of the glycosidic torsion angles are observed to correspond to conformational regions that are highly populated, albeit the ψ torsion angles in the solid state structure deviate somewhat from the pattern observed from the molecular simulations with water as a solvent.
In studies of the conformational dynamics of the title trisaccharide trans-glycosidic heteronuclear carbon-proton coupling constants were measured (Eklund et al., 2005; Jonsson et al., 2011) which, when interpreted by Karplus-type relationships (Säwén et al., 2010), can yield information on conformation via torsion angles at the glycosidic linkages. Calculation of the three-bond coupling constants based on the torsion angles in the φ torsion angles and the ψ torsion angle at the α-(1 → 2)-linkage the differences to the experimental data were not larger than ca 0.5 Hz, indicating that for these torsions the conformation in the solid state is similar to that populated to a large extent in solution. However, for the ψ torsion angle at the α-(1 → 3)-linkage the corresponding difference was larger, ca 1 Hz, suggesting that in the the latter torsion describes a conformation that is less populated in water solution. The conformation is still, however, one in a low region, since conformational exchange occurs for both of the ψ torsion angles between states for which ψ takes either positive or negative values according to the simulation (Eklund et al., 2005).
of the trisaccharide showed that for theThe calculated Cremer & Pople (1975) parameters for the three different rings are: ring O15 → C15 [Q=0.570 (2) Å, θ=177.9 (2) ° and φ=20 (9) °], ring O25 → C25 [Q=0.580 (2) Å, θ=171.4 (2) ° and φ=72.5 (14) °] and for the ring O35 → C35 [Q=0.582 (2) Å, θ=177.1 (2) ° and φ=131 (5) °].
Extensive water-water hydrogen bonding was observed (Table 1) between the title compound and water molecules leading to a water channel in the b-direction (Fig. 2 and Fig. 3). The title compound showed hydrogen bonds to water and to other adjacent (symmetry related) trisaccharides, but no intra-molecular hydrogen bonds were found.
For a description of L-rhamnose as part of
see: Marie et al. (1998); Perry & MacLean (2000). For a description of the conformational dynamics of the title trisaccharide, see: Eklund et al. (2005); Jonsson et al. (2011). For a description of the puckering analysis of the residues, see: Cremer & Pople (1975). For further background to L-rhamnose, see: Ansaruzzaman et al. (1996); Varki et al. (1999); Kulber-Kielb et al. (2007); Lindberg (1998); Säwén et al. (2010).Data collection: SMART (Bruker, 1997); cell
SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: PLATON (Spek, 2009).Fig. 1. A view of the molecule with displacement ellipsoids drawn at the 50% probablity level. | |
Fig. 2. Four unit cells viewed along the b axis with the water molecules symbolized by the large blue discs. The water molecules mediate intermolecular hydrogen bonds between the sugar molecules and along the b axis. | |
Fig. 3. Stereoview of the hydrogen bonded water structure of approximately two unit-cell lengths along the b axis. The water O atoms are shown with blue color and the hydroxyl O atoms are shown with red color. |
C19H34O13·5H2O | F(000) = 1208 |
Mr = 560.54 | Dx = 1.416 Mg m−3 |
Monoclinic, C2 | Synchrotron radiation, λ = 0.8970 Å |
Hall symbol: C 2y | Cell parameters from 963 reflections |
a = 19.345 (3) Å | θ = 2.5–39.8° |
b = 6.4870 (13) Å | µ = 0.22 mm−1 |
c = 21.145 (3) Å | T = 100 K |
β = 97.617 (14)° | Plate, colourless |
V = 2630.0 (8) Å3 | 0.20 × 0.05 × 0.01 mm |
Z = 4 |
Bruker SMART 1K CCD diffractometer | 2906 independent reflections |
Radiation source: Beamline I711, Maxlab | 2655 reflections with I > 2σ(I) |
Silicon monochromator | Rint = 0.046 |
Detector resolution: 10 pixels mm-1 | θmax = 34.1°, θmin = 2.5° |
ω scan at different φ | h = −23→24 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | k = −8→8 |
Tmin = 0.97, Tmax = 0.99 | l = −23→26 |
17172 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.087 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0607P)2] where P = (Fo2 + 2Fc2)/3 |
2906 reflections | (Δ/σ)max < 0.001 |
376 parameters | Δρmax = 0.56 e Å−3 |
16 restraints | Δρmin = −0.29 e Å−3 |
C19H34O13·5H2O | V = 2630.0 (8) Å3 |
Mr = 560.54 | Z = 4 |
Monoclinic, C2 | Synchrotron radiation, λ = 0.8970 Å |
a = 19.345 (3) Å | µ = 0.22 mm−1 |
b = 6.4870 (13) Å | T = 100 K |
c = 21.145 (3) Å | 0.20 × 0.05 × 0.01 mm |
β = 97.617 (14)° |
Bruker SMART 1K CCD diffractometer | 2906 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | 2655 reflections with I > 2σ(I) |
Tmin = 0.97, Tmax = 0.99 | Rint = 0.046 |
17172 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 16 restraints |
wR(F2) = 0.087 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.07 | Δρmax = 0.56 e Å−3 |
2906 reflections | Δρmin = −0.29 e Å−3 |
376 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
OW1 | 0.93266 (10) | −0.3863 (3) | 0.46456 (9) | 0.0236 (4) | |
H101 | 0.9098 (15) | −0.456 (4) | 0.4905 (12) | 0.035* | |
H102 | 0.9424 (17) | −0.474 (4) | 0.4352 (12) | 0.035* | |
OW2 | 0.55372 (9) | −0.3755 (3) | 0.25876 (10) | 0.0244 (4) | |
H201 | 0.5191 (11) | −0.458 (4) | 0.2626 (15) | 0.037* | |
H202 | 0.5911 (10) | −0.422 (5) | 0.2816 (14) | 0.037* | |
OW3 | 0.93523 (9) | 0.2971 (3) | 0.37476 (9) | 0.0213 (4) | |
H301 | 0.9740 (11) | 0.225 (5) | 0.3809 (13) | 0.032* | |
H302 | 0.9301 (15) | 0.339 (5) | 0.3350 (8) | 0.032* | |
OW4 | 0.85929 (11) | −0.0490 (3) | 0.41056 (10) | 0.0321 (5) | |
H401 | 0.8879 (15) | 0.052 (4) | 0.4032 (17) | 0.048* | |
H402 | 0.8891 (14) | −0.133 (4) | 0.4327 (16) | 0.048* | |
OW5 | 1.04589 (10) | 0.0556 (3) | 0.43863 (9) | 0.0271 (4) | |
H501 | 1.0791 (14) | 0.144 (5) | 0.4484 (14) | 0.041* | |
H502 | 1.0265 (15) | 0.022 (5) | 0.4722 (11) | 0.041* | |
C11 | 0.85217 (11) | −0.0103 (3) | 0.23565 (11) | 0.0109 (5) | |
H11 | 0.8527 | 0.0985 | 0.2692 | 0.013* | |
C12 | 0.88270 (11) | −0.2061 (3) | 0.26740 (11) | 0.0116 (5) | |
H12 | 0.8528 | −0.2573 | 0.2992 | 0.014* | |
C13 | 0.88938 (12) | −0.3693 (3) | 0.21708 (11) | 0.0126 (5) | |
H13 | 0.8419 | −0.4074 | 0.1957 | 0.015* | |
C14 | 0.93200 (12) | −0.2870 (3) | 0.16795 (11) | 0.0116 (5) | |
H14 | 0.9806 | −0.2587 | 0.1886 | 0.014* | |
C15 | 0.89936 (12) | −0.0874 (4) | 0.13897 (11) | 0.0121 (5) | |
H15 | 0.8521 | −0.1181 | 0.1157 | 0.014* | |
O15 | 0.89286 (8) | 0.0599 (2) | 0.18944 (7) | 0.0107 (3) | |
O12 | 0.94950 (8) | −0.1441 (2) | 0.29873 (8) | 0.0133 (4) | |
H12A | 0.9670 | −0.2405 | 0.3221 | 0.020* | |
O13 | 0.92191 (9) | −0.5475 (3) | 0.24839 (8) | 0.0174 (4) | |
H13A | 0.9233 | −0.6427 | 0.2217 | 0.026* | |
O14 | 0.93366 (8) | −0.4346 (3) | 0.11879 (8) | 0.0155 (4) | |
H14A | 0.9728 | −0.4926 | 0.1230 | 0.023* | |
C16 | 0.94325 (14) | 0.0139 (4) | 0.09399 (12) | 0.0192 (5) | |
H16A | 0.9205 | 0.1412 | 0.0771 | 0.029* | |
H16B | 0.9485 | −0.0801 | 0.0586 | 0.029* | |
H16C | 0.9893 | 0.0465 | 0.1169 | 0.029* | |
C21 | 0.74537 (12) | 0.1967 (4) | 0.12541 (11) | 0.0135 (5) | |
H21 | 0.7951 | 0.1923 | 0.1173 | 0.016* | |
C22 | 0.74289 (11) | 0.1369 (3) | 0.19460 (11) | 0.0109 (5) | |
H22 | 0.7628 | 0.2513 | 0.2231 | 0.013* | |
O22 | 0.78200 (8) | −0.0481 (2) | 0.21047 (7) | 0.0106 (3) | |
C23 | 0.66745 (11) | 0.0994 (3) | 0.20516 (11) | 0.0105 (5) | |
H23 | 0.6417 | 0.2329 | 0.1986 | 0.013* | |
C24 | 0.63267 (11) | −0.0554 (4) | 0.15733 (11) | 0.0120 (5) | |
H24 | 0.6584 | −0.1893 | 0.1615 | 0.014* | |
C25 | 0.63456 (12) | 0.0347 (4) | 0.09175 (11) | 0.0147 (5) | |
H25 | 0.6115 | 0.1730 | 0.0896 | 0.018* | |
O23 | 0.66298 (8) | 0.0302 (2) | 0.26878 (7) | 0.0111 (3) | |
O24 | 0.56178 (8) | −0.0859 (3) | 0.16682 (8) | 0.0151 (4) | |
H24A | 0.5600 | −0.1706 | 0.1966 | 0.023* | |
O25 | 0.70645 (8) | 0.0599 (3) | 0.08206 (8) | 0.0150 (4) | |
C26 | 0.59920 (13) | −0.0981 (5) | 0.03875 (12) | 0.0228 (6) | |
H26A | 0.6034 | −0.0334 | −0.0024 | 0.034* | |
H26B | 0.5498 | −0.1132 | 0.0436 | 0.034* | |
H26C | 0.6213 | −0.2342 | 0.0406 | 0.034* | |
O27 | 0.72203 (9) | 0.4015 (2) | 0.11823 (8) | 0.0160 (4) | |
C27 | 0.74020 (15) | 0.4932 (5) | 0.06129 (14) | 0.0277 (6) | |
H27A | 0.7895 | 0.4660 | 0.0581 | 0.042* | |
H27B | 0.7324 | 0.6423 | 0.0625 | 0.042* | |
H27C | 0.7112 | 0.4341 | 0.0242 | 0.042* | |
C31 | 0.62082 (12) | 0.1575 (4) | 0.30105 (11) | 0.0110 (5) | |
H31 | 0.5776 | 0.1923 | 0.2715 | 0.013* | |
C32 | 0.60030 (11) | 0.0409 (4) | 0.35762 (10) | 0.0110 (5) | |
H32 | 0.5808 | −0.0956 | 0.3422 | 0.013* | |
C33 | 0.66440 (12) | 0.0023 (3) | 0.40588 (11) | 0.0106 (5) | |
H33 | 0.6966 | −0.0894 | 0.3854 | 0.013* | |
C34 | 0.70281 (12) | 0.2040 (3) | 0.42416 (11) | 0.0108 (5) | |
H34 | 0.6719 | 0.2960 | 0.4460 | 0.013* | |
C35 | 0.72015 (12) | 0.3104 (3) | 0.36380 (11) | 0.0111 (5) | |
H35 | 0.7515 | 0.2194 | 0.3422 | 0.013* | |
O35 | 0.65577 (8) | 0.3437 (2) | 0.32144 (7) | 0.0117 (3) | |
O32 | 0.54699 (8) | 0.1518 (3) | 0.38395 (8) | 0.0126 (3) | |
H32A | 0.5645 | 0.2558 | 0.4037 | 0.019* | |
O33 | 0.64458 (8) | −0.1032 (2) | 0.45946 (8) | 0.0133 (4) | |
H33A | 0.6805 | −0.1388 | 0.4838 | 0.020* | |
O34 | 0.76396 (8) | 0.1594 (3) | 0.46677 (8) | 0.0157 (4) | |
H34A | 0.7898 | 0.0805 | 0.4488 | 0.024* | |
C36 | 0.75423 (13) | 0.5176 (4) | 0.37637 (12) | 0.0187 (5) | |
H36A | 0.7546 | 0.5910 | 0.3359 | 0.028* | |
H36B | 0.8023 | 0.4985 | 0.3969 | 0.028* | |
H36C | 0.7281 | 0.5980 | 0.4044 | 0.028* |
U11 | U22 | U33 | U12 | U13 | U23 | |
OW1 | 0.0248 (10) | 0.0236 (10) | 0.0246 (10) | 0.0013 (8) | 0.0114 (8) | −0.0030 (8) |
OW2 | 0.0130 (9) | 0.0193 (9) | 0.0394 (12) | −0.0022 (8) | −0.0019 (8) | 0.0144 (8) |
OW3 | 0.0211 (10) | 0.0208 (9) | 0.0218 (10) | −0.0004 (8) | 0.0019 (8) | −0.0010 (8) |
OW4 | 0.0354 (12) | 0.0274 (11) | 0.0349 (12) | −0.0050 (10) | 0.0102 (10) | 0.0050 (9) |
OW5 | 0.0270 (11) | 0.0176 (9) | 0.0343 (11) | −0.0025 (8) | −0.0046 (9) | 0.0022 (9) |
C11 | 0.0078 (11) | 0.0104 (10) | 0.0138 (11) | −0.0012 (9) | −0.0008 (9) | −0.0032 (9) |
C12 | 0.0066 (11) | 0.0135 (11) | 0.0143 (12) | −0.0022 (9) | 0.0000 (9) | −0.0007 (9) |
C13 | 0.0112 (11) | 0.0085 (10) | 0.0171 (12) | −0.0003 (9) | −0.0018 (9) | 0.0011 (9) |
C14 | 0.0086 (11) | 0.0113 (10) | 0.0139 (11) | 0.0015 (9) | −0.0025 (9) | −0.0015 (9) |
C15 | 0.0108 (11) | 0.0108 (10) | 0.0140 (12) | −0.0002 (9) | −0.0006 (9) | −0.0005 (9) |
O15 | 0.0098 (8) | 0.0089 (7) | 0.0133 (8) | 0.0001 (6) | 0.0020 (6) | −0.0003 (7) |
O12 | 0.0097 (8) | 0.0133 (8) | 0.0149 (9) | 0.0010 (7) | −0.0055 (6) | 0.0006 (7) |
O13 | 0.0251 (9) | 0.0082 (8) | 0.0185 (9) | 0.0040 (7) | 0.0017 (7) | 0.0012 (7) |
O14 | 0.0131 (8) | 0.0163 (8) | 0.0164 (9) | 0.0063 (7) | −0.0006 (7) | −0.0047 (7) |
C16 | 0.0241 (14) | 0.0176 (12) | 0.0172 (13) | 0.0002 (10) | 0.0075 (10) | 0.0026 (10) |
C21 | 0.0104 (12) | 0.0126 (11) | 0.0179 (12) | 0.0031 (9) | 0.0032 (9) | 0.0022 (10) |
C22 | 0.0080 (11) | 0.0083 (10) | 0.0161 (12) | 0.0034 (9) | 0.0009 (9) | −0.0015 (9) |
O22 | 0.0055 (8) | 0.0099 (7) | 0.0156 (8) | 0.0017 (6) | −0.0012 (6) | 0.0010 (6) |
C23 | 0.0092 (11) | 0.0120 (11) | 0.0100 (11) | 0.0023 (9) | 0.0003 (8) | 0.0011 (9) |
C24 | 0.0054 (10) | 0.0154 (11) | 0.0154 (11) | 0.0028 (9) | 0.0014 (9) | −0.0010 (10) |
C25 | 0.0100 (11) | 0.0196 (12) | 0.0139 (12) | 0.0027 (10) | −0.0010 (9) | 0.0000 (10) |
O23 | 0.0088 (8) | 0.0131 (8) | 0.0113 (8) | 0.0038 (6) | 0.0016 (6) | 0.0013 (7) |
O24 | 0.0084 (8) | 0.0199 (9) | 0.0167 (9) | −0.0017 (7) | 0.0007 (6) | 0.0043 (7) |
O25 | 0.0124 (8) | 0.0204 (9) | 0.0123 (8) | 0.0013 (7) | 0.0018 (6) | −0.0015 (7) |
C26 | 0.0146 (13) | 0.0365 (15) | 0.0163 (13) | −0.0014 (11) | −0.0014 (10) | −0.0060 (12) |
O27 | 0.0161 (9) | 0.0126 (8) | 0.0199 (9) | 0.0052 (7) | 0.0050 (7) | 0.0070 (7) |
C27 | 0.0283 (15) | 0.0270 (14) | 0.0291 (15) | 0.0056 (12) | 0.0082 (12) | 0.0162 (12) |
C31 | 0.0073 (10) | 0.0126 (10) | 0.0128 (11) | 0.0009 (9) | −0.0004 (8) | −0.0017 (9) |
C32 | 0.0092 (11) | 0.0102 (10) | 0.0131 (11) | −0.0006 (9) | −0.0004 (9) | −0.0008 (9) |
C33 | 0.0118 (11) | 0.0079 (10) | 0.0124 (11) | 0.0010 (9) | 0.0030 (9) | 0.0017 (9) |
C34 | 0.0101 (11) | 0.0097 (10) | 0.0123 (11) | 0.0004 (9) | −0.0003 (9) | −0.0017 (9) |
C35 | 0.0074 (11) | 0.0118 (11) | 0.0137 (12) | 0.0013 (9) | −0.0005 (9) | −0.0012 (9) |
O35 | 0.0111 (8) | 0.0106 (7) | 0.0125 (8) | 0.0002 (6) | −0.0015 (6) | 0.0001 (6) |
O32 | 0.0087 (8) | 0.0153 (8) | 0.0142 (8) | 0.0009 (7) | 0.0029 (6) | 0.0009 (7) |
O33 | 0.0105 (8) | 0.0141 (8) | 0.0142 (8) | 0.0013 (7) | −0.0024 (6) | 0.0036 (7) |
O34 | 0.0103 (8) | 0.0193 (9) | 0.0165 (9) | 0.0017 (7) | −0.0022 (7) | 0.0008 (7) |
C36 | 0.0204 (13) | 0.0152 (12) | 0.0201 (13) | −0.0065 (10) | 0.0006 (10) | −0.0002 (10) |
OW1—H101 | 0.875 (15) | C23—O23 | 1.432 (3) |
OW1—H102 | 0.879 (15) | C23—C24 | 1.517 (3) |
OW2—H201 | 0.871 (15) | C23—H23 | 1.0000 |
OW2—H202 | 0.869 (15) | C24—O24 | 1.426 (3) |
OW3—H301 | 0.878 (14) | C24—C25 | 1.510 (3) |
OW3—H302 | 0.877 (14) | C24—H24 | 1.0000 |
OW4—H401 | 0.883 (15) | C25—O25 | 1.442 (3) |
OW4—H402 | 0.883 (15) | C25—C26 | 1.504 (3) |
OW5—H501 | 0.867 (15) | C25—H25 | 1.0000 |
OW5—H502 | 0.873 (14) | O23—C31 | 1.400 (3) |
C11—O15 | 1.409 (3) | O24—H24A | 0.8400 |
C11—O22 | 1.412 (3) | C26—H26A | 0.9800 |
C11—C12 | 1.519 (3) | C26—H26B | 0.9800 |
C11—H11 | 1.0000 | C26—H26C | 0.9800 |
C12—O12 | 1.429 (3) | O27—C27 | 1.428 (3) |
C12—C13 | 1.519 (3) | C27—H27A | 0.9800 |
C12—H12 | 1.0000 | C27—H27B | 0.9800 |
C13—O13 | 1.435 (3) | C27—H27C | 0.9800 |
C13—C14 | 1.507 (3) | C31—O35 | 1.423 (3) |
C13—H13 | 1.0000 | C31—C32 | 1.512 (3) |
C14—O14 | 1.417 (3) | C31—H31 | 1.0000 |
C14—C15 | 1.532 (3) | C32—O32 | 1.429 (3) |
C14—H14 | 1.0000 | C32—C33 | 1.519 (3) |
C15—O15 | 1.451 (3) | C32—H32 | 1.0000 |
C15—C16 | 1.507 (3) | C33—O33 | 1.419 (3) |
C15—H15 | 1.0000 | C33—C34 | 1.529 (3) |
O12—H12A | 0.8400 | C33—H33 | 1.0000 |
O13—H13A | 0.8400 | C34—O34 | 1.419 (3) |
O14—H14A | 0.8400 | C34—C35 | 1.527 (3) |
C16—H16A | 0.9800 | C34—H34 | 1.0000 |
C16—H16B | 0.9800 | C35—O35 | 1.451 (3) |
C16—H16C | 0.9800 | C35—C36 | 1.505 (3) |
C21—O27 | 1.405 (3) | C35—H35 | 1.0000 |
C21—O25 | 1.419 (3) | O32—H32A | 0.8400 |
C21—C22 | 1.521 (3) | O33—H33A | 0.8400 |
C21—H21 | 1.0000 | O34—H34A | 0.8400 |
C22—O22 | 1.434 (3) | C36—H36A | 0.9800 |
C22—C23 | 1.525 (3) | C36—H36B | 0.9800 |
C22—H22 | 1.0000 | C36—H36C | 0.9800 |
H101—OW1—H102 | 106 (2) | C25—C24—C23 | 107.07 (19) |
H201—OW2—H202 | 109 (2) | O24—C24—H24 | 110.2 |
H301—OW3—H302 | 107 (2) | C25—C24—H24 | 110.2 |
H401—OW4—H402 | 100 (2) | C23—C24—H24 | 110.2 |
H501—OW5—H502 | 111 (2) | O25—C25—C26 | 108.12 (19) |
O15—C11—O22 | 113.08 (18) | O25—C25—C24 | 108.40 (17) |
O15—C11—C12 | 110.89 (18) | C26—C25—C24 | 113.5 (2) |
O22—C11—C12 | 108.63 (17) | O25—C25—H25 | 108.9 |
O15—C11—H11 | 108.0 | C26—C25—H25 | 108.9 |
O22—C11—H11 | 108.0 | C24—C25—H25 | 108.9 |
C12—C11—H11 | 108.0 | C31—O23—C23 | 112.64 (17) |
O12—C12—C13 | 111.41 (18) | C24—O24—H24A | 109.5 |
O12—C12—C11 | 104.15 (17) | C21—O25—C25 | 114.75 (17) |
C13—C12—C11 | 109.73 (18) | C25—C26—H26A | 109.5 |
O12—C12—H12 | 110.5 | C25—C26—H26B | 109.5 |
C13—C12—H12 | 110.5 | H26A—C26—H26B | 109.5 |
C11—C12—H12 | 110.5 | C25—C26—H26C | 109.5 |
O13—C13—C14 | 110.90 (19) | H26A—C26—H26C | 109.5 |
O13—C13—C12 | 108.14 (18) | H26B—C26—H26C | 109.5 |
C14—C13—C12 | 109.94 (19) | C21—O27—C27 | 111.92 (19) |
O13—C13—H13 | 109.3 | O27—C27—H27A | 109.5 |
C14—C13—H13 | 109.3 | O27—C27—H27B | 109.5 |
C12—C13—H13 | 109.3 | H27A—C27—H27B | 109.5 |
O14—C14—C13 | 109.53 (18) | O27—C27—H27C | 109.5 |
O14—C14—C15 | 109.00 (18) | H27A—C27—H27C | 109.5 |
C13—C14—C15 | 109.94 (19) | H27B—C27—H27C | 109.5 |
O14—C14—H14 | 109.5 | O23—C31—O35 | 111.35 (18) |
C13—C14—H14 | 109.5 | O23—C31—C32 | 108.77 (18) |
C15—C14—H14 | 109.5 | O35—C31—C32 | 110.42 (18) |
O15—C15—C16 | 106.72 (19) | O23—C31—H31 | 108.7 |
O15—C15—C14 | 109.51 (17) | O35—C31—H31 | 108.7 |
C16—C15—C14 | 112.6 (2) | C32—C31—H31 | 108.7 |
O15—C15—H15 | 109.3 | O32—C32—C31 | 109.59 (18) |
C16—C15—H15 | 109.3 | O32—C32—C33 | 112.85 (18) |
C14—C15—H15 | 109.3 | C31—C32—C33 | 109.72 (18) |
C11—O15—C15 | 114.07 (17) | O32—C32—H32 | 108.2 |
C12—O12—H12A | 109.5 | C31—C32—H32 | 108.2 |
C13—O13—H13A | 109.5 | C33—C32—H32 | 108.2 |
C14—O14—H14A | 109.5 | O33—C33—C32 | 109.45 (18) |
C15—C16—H16A | 109.5 | O33—C33—C34 | 112.62 (18) |
C15—C16—H16B | 109.5 | C32—C33—C34 | 110.77 (18) |
H16A—C16—H16B | 109.5 | O33—C33—H33 | 107.9 |
C15—C16—H16C | 109.5 | C32—C33—H33 | 107.9 |
H16A—C16—H16C | 109.5 | C34—C33—H33 | 107.9 |
H16B—C16—H16C | 109.5 | O34—C34—C35 | 111.48 (18) |
O27—C21—O25 | 112.73 (18) | O34—C34—C33 | 108.79 (18) |
O27—C21—C22 | 107.14 (19) | C35—C34—C33 | 109.19 (17) |
O25—C21—C22 | 112.34 (19) | O34—C34—H34 | 109.1 |
O27—C21—H21 | 108.2 | C35—C34—H34 | 109.1 |
O25—C21—H21 | 108.2 | C33—C34—H34 | 109.1 |
C22—C21—H21 | 108.2 | O35—C35—C36 | 107.24 (18) |
O22—C22—C21 | 110.84 (18) | O35—C35—C34 | 108.53 (18) |
O22—C22—C23 | 108.53 (17) | C36—C35—C34 | 113.29 (19) |
C21—C22—C23 | 109.54 (18) | O35—C35—H35 | 109.2 |
O22—C22—H22 | 109.3 | C36—C35—H35 | 109.2 |
C21—C22—H22 | 109.3 | C34—C35—H35 | 109.2 |
C23—C22—H22 | 109.3 | C31—O35—C35 | 113.29 (16) |
C11—O22—C22 | 113.20 (16) | C32—O32—H32A | 109.5 |
O23—C23—C24 | 110.01 (18) | C33—O33—H33A | 109.5 |
O23—C23—C22 | 111.45 (17) | C34—O34—H34A | 109.5 |
C24—C23—C22 | 110.88 (18) | C35—C36—H36A | 109.5 |
O23—C23—H23 | 108.1 | C35—C36—H36B | 109.5 |
C24—C23—H23 | 108.1 | H36A—C36—H36B | 109.5 |
C22—C23—H23 | 108.1 | C35—C36—H36C | 109.5 |
O24—C24—C25 | 108.90 (17) | H36A—C36—H36C | 109.5 |
O24—C24—C23 | 110.37 (18) | H36B—C36—H36C | 109.5 |
O15—C11—C12—O12 | 63.1 (2) | C22—C23—C24—C25 | −60.4 (2) |
O22—C11—C12—O12 | −172.08 (17) | O24—C24—C25—O25 | −178.52 (18) |
O15—C11—C12—C13 | −56.3 (2) | C23—C24—C25—O25 | 62.1 (2) |
O22—C11—C12—C13 | 68.6 (2) | O24—C24—C25—C26 | −58.4 (3) |
O12—C12—C13—O13 | 62.0 (2) | C23—C24—C25—C26 | −177.72 (19) |
C11—C12—C13—O13 | 176.82 (17) | C24—C23—O23—C31 | −113.6 (2) |
O12—C12—C13—C14 | −59.2 (2) | C22—C23—O23—C31 | 122.95 (19) |
C11—C12—C13—C14 | 55.6 (2) | O27—C21—O25—C25 | −65.9 (2) |
O13—C13—C14—O14 | 64.7 (2) | C22—C21—O25—C25 | 55.2 (2) |
C12—C13—C14—O14 | −175.75 (17) | C26—C25—O25—C21 | 174.83 (19) |
O13—C13—C14—C15 | −175.54 (17) | C24—C25—O25—C21 | −61.7 (2) |
C12—C13—C14—C15 | −56.0 (2) | O25—C21—O27—C27 | −72.3 (2) |
O14—C14—C15—O15 | 176.01 (17) | C22—C21—O27—C27 | 163.6 (2) |
C13—C14—C15—O15 | 55.9 (2) | C23—O23—C31—O35 | −76.1 (2) |
O14—C14—C15—C16 | −65.4 (2) | C23—O23—C31—C32 | 162.03 (16) |
C13—C14—C15—C16 | 174.51 (19) | O23—C31—C32—O32 | −169.04 (17) |
O22—C11—O15—C15 | −63.2 (2) | O35—C31—C32—O32 | 68.5 (2) |
C12—C11—O15—C15 | 59.1 (2) | O23—C31—C32—C33 | 66.5 (2) |
C16—C15—O15—C11 | 179.25 (18) | O35—C31—C32—C33 | −55.9 (2) |
C14—C15—O15—C11 | −58.6 (2) | O32—C32—C33—O33 | 56.2 (2) |
O27—C21—C22—O22 | −165.21 (16) | C31—C32—C33—O33 | 178.75 (18) |
O25—C21—C22—O22 | 70.5 (2) | O32—C32—C33—C34 | −68.5 (2) |
O27—C21—C22—C23 | 75.1 (2) | C31—C32—C33—C34 | 54.0 (2) |
O25—C21—C22—C23 | −49.3 (2) | O33—C33—C34—O34 | 59.9 (2) |
O15—C11—O22—C22 | −72.0 (2) | C32—C33—C34—O34 | −177.17 (18) |
C12—C11—O22—C22 | 164.44 (18) | O33—C33—C34—C35 | −178.26 (18) |
C21—C22—O22—C11 | 91.8 (2) | C32—C33—C34—C35 | −55.3 (2) |
C23—C22—O22—C11 | −147.87 (18) | O34—C34—C35—O35 | 177.68 (17) |
O22—C22—C23—O23 | 55.3 (2) | C33—C34—C35—O35 | 57.5 (2) |
C21—C22—C23—O23 | 176.42 (18) | O34—C34—C35—C36 | −63.3 (2) |
O22—C22—C23—C24 | −67.6 (2) | C33—C34—C35—C36 | 176.44 (19) |
C21—C22—C23—C24 | 53.5 (2) | O23—C31—O35—C35 | −59.2 (2) |
O23—C23—C24—O24 | 57.5 (2) | C32—C31—O35—C35 | 61.8 (2) |
C22—C23—C24—O24 | −178.80 (17) | C36—C35—O35—C31 | 174.92 (19) |
O23—C23—C24—C25 | 175.84 (17) | C34—C35—O35—C31 | −62.4 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
OW1—H101···O33i | 0.88 (3) | 1.85 (3) | 2.726 (2) | 176 (2) |
OW1—H102···OW3ii | 0.88 (3) | 1.95 (3) | 2.802 (2) | 162 (2) |
OW1—H102···O32iii | 0.88 (3) | 2.55 (3) | 2.976 (2) | 110 (2) |
OW2—H201···O12iv | 0.88 (3) | 2.03 (3) | 2.875 (2) | 163 (2) |
OW2—H202···O35ii | 0.87 (3) | 2.08 (3) | 2.877 (2) | 153 (2) |
OW3—H301···OW5 | 0.88 (3) | 2.04 (3) | 2.845 (2) | 151 (2) |
OW3—H302···O13v | 0.88 (3) | 1.96 (3) | 2.836 (2) | 176 (2) |
OW4—H401···OW3 | 0.88 (3) | 1.97 (3) | 2.840 (2) | 168 (2) |
OW4—H402···OW1 | 0.88 (3) | 1.92 (3) | 2.771 (2) | 160 (2) |
OW5—H501···O33vi | 0.87 (3) | 2.07 (3) | 2.918 (2) | 168 (2) |
OW5—H502···OW5vii | 0.87 (3) | 2.50 (3) | 3.333 (2) | 159 (2) |
O12—H12A···O32iii | 0.84 | 2.01 | 2.767 (2) | 149 |
O13—H13A···O15ii | 0.84 | 2.10 | 2.858 (2) | 149 |
O14—H14A···O24iii | 0.84 | 1.95 | 2.733 (2) | 157 |
O24—H24A···OW2 | 0.84 | 1.88 | 2.722 (2) | 176 |
O32—H32A···OW5viii | 0.84 | 2.13 | 2.864 (2) | 146 |
O33—H33A···O34i | 0.84 | 1.91 | 2.684 (2) | 152 |
O34—H34A···OW4 | 0.84 | 1.86 | 2.687 (2) | 168 |
Symmetry codes: (i) −x+3/2, y−1/2, −z+1; (ii) x, y−1, z; (iii) x+1/2, y−1/2, z; (iv) x−1/2, y−1/2, z; (v) x, y+1, z; (vi) x+1/2, y+1/2, z; (vii) −x+2, y, −z+1; (viii) x−1/2, y+1/2, z. |
Experimental details
Crystal data | |
Chemical formula | C19H34O13·5H2O |
Mr | 560.54 |
Crystal system, space group | Monoclinic, C2 |
Temperature (K) | 100 |
a, b, c (Å) | 19.345 (3), 6.4870 (13), 21.145 (3) |
β (°) | 97.617 (14) |
V (Å3) | 2630.0 (8) |
Z | 4 |
Radiation type | Synchrotron, λ = 0.8970 Å |
µ (mm−1) | 0.22 |
Crystal size (mm) | 0.20 × 0.05 × 0.01 |
Data collection | |
Diffractometer | Bruker SMART 1K CCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2002) |
Tmin, Tmax | 0.97, 0.99 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 17172, 2906, 2655 |
Rint | 0.046 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.087, 1.07 |
No. of reflections | 2906 |
No. of parameters | 376 |
No. of restraints | 16 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.56, −0.29 |
Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999), PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
OW1—H101···O33i | 0.88 (3) | 1.85 (3) | 2.726 (2) | 176 (2) |
OW1—H102···OW3ii | 0.88 (3) | 1.95 (3) | 2.802 (2) | 162 (2) |
OW1—H102···O32iii | 0.88 (3) | 2.55 (3) | 2.976 (2) | 110 (2) |
OW2—H201···O12iv | 0.88 (3) | 2.03 (3) | 2.875 (2) | 163 (2) |
OW2—H202···O35ii | 0.87 (3) | 2.08 (3) | 2.877 (2) | 153 (2) |
OW3—H301···OW5 | 0.88 (3) | 2.04 (3) | 2.845 (2) | 151 (2) |
OW3—H302···O13v | 0.88 (3) | 1.96 (3) | 2.836 (2) | 176 (2) |
OW4—H401···OW3 | 0.88 (3) | 1.97 (3) | 2.840 (2) | 168 (2) |
OW4—H402···OW1 | 0.88 (3) | 1.92 (3) | 2.771 (2) | 160 (2) |
OW5—H501···O33vi | 0.87 (3) | 2.07 (3) | 2.918 (2) | 168 (2) |
OW5—H502···OW5vii | 0.87 (3) | 2.50 (3) | 3.333 (2) | 159 (2) |
O12—H12A···O32iii | 0.84 | 2.013 | 2.767 (2) | 149 |
O13—H13A···O15ii | 0.84 | 2.104 | 2.858 (2) | 149 |
O14—H14A···O24iii | 0.84 | 1.949 | 2.733 (2) | 157 |
O24—H24A···OW2 | 0.84 | 1.884 | 2.722 (2) | 176 |
O32—H32A···OW5viii | 0.84 | 2.128 | 2.864 (2) | 146 |
O33—H33A···O34i | 0.84 | 1.914 | 2.684 (2) | 152 |
O34—H34A···OW4 | 0.84 | 1.859 | 2.687 (2) | 168 |
Symmetry codes: (i) −x+3/2, y−1/2, −z+1; (ii) x, y−1, z; (iii) x+1/2, y−1/2, z; (iv) x−1/2, y−1/2, z; (v) x, y+1, z; (vi) x+1/2, y+1/2, z; (vii) −x+2, y, −z+1; (viii) x−1/2, y+1/2, z. |
Acknowledgements
This work was supported by a grant from the Swedish Research Council (VR).
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
In carbohydrate structures from humans the number of different monosaccharides is quite limited; typically seven different sugars are present in glycoproteins and glycolipids (Varki et al., 1999). Constituents of polysaccharides in man add a few more monosaccharides to the repertoire. In bacteria, however, more than 100 different monosaccharide components have been found (Lindberg, 1998). One of them, L-rhamnose (6-deoxy-L-mannose) is present as a major constituent of the O-antigen polysaccharides from Shigella flexneri (Kulber-Kielb et al., 2007) and is the sole monosaccharide in the repeating unit of an O-antigen from a Klebsiella pneumoniae strain (Ansaruzzaman et al., 1996). L-rhamnose is also found a the branch point sugar in some polysaccharides, e.g., from Escherichia coli O139 (Marie et al., 1998) and Yersinia enterocolitica serotype O:28 (Perry & MacLean, 2000).
In the title compound (I) the three sugar components are all L-rhamnose residues having the α-anomeric configuration. The O-methyl residue (a) is vicinally disubstituted at O2 (residue b) and O3 (residue c) which leads to spatial proximity of also the two latter rhamnosyl groups. The major degrees of freedom in trisaccharide (I) are present at the (1 → 2)- and (1 → 3)-linkages, i.e., between residues b and a as well as between residues c and a, respectively. The torsion angles are given by φ2 = 48°, ψ2 = -29°, φ3 = 44° and ψ3 = 4°. In a recent NMR and molecular dynamics (MD) simulation study of (I) in water solution <φ> ≈ 40°, when the exo-anomeric conformation was populated, but non-exo conformations with φ < 0° were also significantly populated (Eklund et al., 2005). The dynamics of the ψ torsion angles were found to be highly correlated with both ψ2 and ψ3 being either > 0° or < 0°. The conformation of the X-ray structure (Figure 1) is reminiscent of the conformational states found from the MD simulation and the values of the glycosidic torsion angles are observed to correspond to conformational regions that are highly populated, albeit the ψ torsion angles in the solid state structure deviate somewhat from the pattern observed from the molecular simulations with water as a solvent.
In studies of the conformational dynamics of the title trisaccharide trans-glycosidic heteronuclear carbon-proton coupling constants were measured (Eklund et al., 2005; Jonsson et al., 2011) which, when interpreted by Karplus-type relationships (Säwén et al., 2010), can yield information on conformation via torsion angles at the glycosidic linkages. Calculation of the three-bond coupling constants based on the torsion angles in the crystal structure of the trisaccharide showed that for the φ torsion angles and the ψ torsion angle at the α-(1 → 2)-linkage the differences to the experimental data were not larger than ca 0.5 Hz, indicating that for these torsions the conformation in the solid state is similar to that populated to a large extent in solution. However, for the ψ torsion angle at the α-(1 → 3)-linkage the corresponding difference was larger, ca 1 Hz, suggesting that in the crystal structure the latter torsion describes a conformation that is less populated in water solution. The crystal structure conformation is still, however, one in a low potential energy region, since conformational exchange occurs for both of the ψ torsion angles between states for which ψ takes either positive or negative values according to the molecular dynamics simulation (Eklund et al., 2005).
The calculated Cremer & Pople (1975) parameters for the three different rings are: ring O15 → C15 [Q=0.570 (2) Å, θ=177.9 (2) ° and φ=20 (9) °], ring O25 → C25 [Q=0.580 (2) Å, θ=171.4 (2) ° and φ=72.5 (14) °] and for the ring O35 → C35 [Q=0.582 (2) Å, θ=177.1 (2) ° and φ=131 (5) °].
Extensive water-water hydrogen bonding was observed (Table 1) between the title compound and water molecules leading to a water channel in the b-direction (Fig. 2 and Fig. 3). The title compound showed hydrogen bonds to water and to other adjacent (symmetry related) trisaccharides, but no intra-molecular hydrogen bonds were found.