organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

N-(4-Iso­cyano­phen­yl)succinamic acid

aDepartment of Chemistry, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC 28223, USA
*Correspondence e-mail: jmrisley@uncc.edu, djones@uncc.edu

(Received 24 January 2012; accepted 3 June 2012; online 13 June 2012)

In the crystal structure of the title compound, C11H10N2O3, inversion-related mol­ecules are connected by pairs of O—H⋯O hydrogen bonds. With the exception of the atoms in the carb­oxy­lic acid group, the non-H atoms are roughly coplanar with a maximum deviation from the mean plane of 0.270 (1) Å for the C atom to which the carb­oxy­lic group is attached. The C atom of the carb­oxy­lic group lies 1.730 (2) Å from the mean plane.

Related literature

For the structure of 4-isocyano­aniline see: Britton (1993[Britton, D. (1993). J. Crystallogr. Spectrosc. Res. 23, 689-690.]). For details of the enzyme-catalysed reaction, see: Risley et al. (2001[Risley, J. M., Huang, D. H., Kaylor, J. J., Malik, J. J., Xia, Y. Q. & York, W. M. (2001). Arch. Biochem. Biophys. 391, 165-170.]); Du & Risley (2003[Du, W. & Risley, J. M. (2003). Org. Biomol. Chem. 1, 1900-1905.]). For the synthetic procedures, see: Heinze & Jacob (2003[Heinze, K. & Jacob, V. (2003). Eur. J. Inorg. Chem. pp. 3918-3923.]); Kar & Argade (2002[Kar, A. & Argade, N. P. (2002). Synthesis, pp. 221-224.]).

[Scheme 1]

Experimental

Crystal data
  • C11H10N2O3

  • Mr = 218.21

  • Monoclinic, P 21 /c

  • a = 5.0974 (2) Å

  • b = 16.2774 (7) Å

  • c = 12.5674 (6) Å

  • β = 94.771 (4)°

  • V = 1039.13 (8) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 0.87 mm−1

  • T = 100 K

  • 0.42 × 0.09 × 0.08 mm

Data collection
  • Agilent Xcalibur Atlas Gemini ultra diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]) Tmin = 0.746, Tmax = 1

  • 7543 measured reflections

  • 1839 independent reflections

  • 1527 reflections with I > 2σ(I)

  • Rint = 0.035

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.096

  • S = 1.07

  • 1839 reflections

  • 153 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O3—HO3⋯O2i 0.94 (3) 1.72 (3) 2.6646 (17) 177 (2)
Symmetry code: (i) -x+1, -y+1, -z+2.

Data collection: CrysAlis PRO (Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Glycosylasparaginase is a key lysosomal enzyme in the catabolism of N-linked glycoproteins. The natural substrate for the enzyme is N4-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-L-asparagine. In a study of the enzyme-catalyzed reaction in which the structure of the amino acid part of the natural substrate was altered (and the sugar was unchanged), it was found that the binding sites on the enzyme for the sugar and the α-carboxyl group were sufficient for the enzyme to act on the substrate, with the α-amino group acting as an "anchor" in the binding site for the substrate (Risley et al., 2001). In a follow-up study, a series of N4-(4'-substituted phenyl)-L-asparagines were synthesized in which the structure of the amino acid part of the natural substrate was unchanged, but the sugar was substituted with para-substituted anilines. All of these β-anilides of asparagine were substrates for the enzyme (Du & Risley, 2003).

In order to better understand the role of the α-amino group in the binding to the enzyme, results from the two studies were used to design a series of N4-(4'-substituted phenyl)succinamic acids in which the structure of the amino acid part of the natural substrate was changed to succinamic acid (the α-amino group was replaced with a hydrogen) and the sugar part was substituted with para-substituted anilines. One of the substrate analogues synthesized was the title compound, with the atypical electron-withdrawing isocyano group that should make 4-isocyanoaniline a very good leaving group in the hydrolysis of the amide bond during the enzyme-catalyzed reaction. Initial studies of these analogues with the enzyme, however, indicated that they were neither substrates nor inhibitors. These initial studies would indicate that, for anilide substrates, the α-amino group is required for binding of the substrate to the active site of the enzyme, in contrast to the sugar substrates for which the α-amino group was not required.

The pair of molecules related by the inversion center at (1/2,1/2,0) are joined by two symmetry-equivalent O—H···O hydrogen bonds, as shown in Figure 2 and described in Table 1. The non-hydrogen atoms of the molecule are nearly planar, with the exception of those in the carboxylic acid group. A mean plane was fit to all of the non-hydrogen atoms except those of the carboxylic group; the maximum deviation of the fitted atoms is 0.270 (1) Å, for C10. The carbon of the carboxylic group, C11, lies 1.730 (2) Å from the mean plane.

Related literature top

For the structure of 4-isocyanoaniline see: Britton (1993). For details of the enzyme-catalysed reaction, see: Risley et al. (2001); Du & Risley (2003). For the synthetic procedures, see: Heinze & Jacob (2003); Kar & Argade (2002).

Experimental top

4-Isocyanoaniline was synthesized as described in the literature (Heinze & Jacob, 2003). The general procedure described by Kar and Argade (Kar & Argade, 2002) was then used to synthesize the title compound. 4-Isocyanoaniline (1.18 g, 0.01 mol) and succinic anhydride (1 g, 0.01 mol) were added to benzene:1,4-dioxane (2:1, 60 ml) and stirred at room temperature for 24 h to give needles that were collected and washed with the benzene:dioxane solvent. Yield 1.22 g (0.006 mol, 56%).

Mp 424 K. 1H NMR: δH (300.53 MHz, CD3OD) 2.677 (4H, center of AA'BB' spectrum: ΔnAB 4.10 Hz, JAB 7.44 Hz, JAB' 6.00 Hz, JAA' -16.00 Hz, JBB' -17.00 Hz, H-2,3), 7.378 (2H, BB' of AA'BB', JAB 8.56, JAB' 0.40, JBB' 2.50, H-3',5'), 7.655 (2H, AA' of AA'BB', JAA' 2.20, H-2',6'), 9.510 (1H, s, NH), OH not observed. 13C NMR: δC (125.77 MHz, DMSO-d6) 28.634 (C2), 31.122 (C3), 119.287 (C3'/5'), 119.358 (C5'/3'), 120.064 (C4'), 126.991 (C2'/6'), 127.161 (C6'/2'), 140.404 (C1'), 162.982 (NC), 170.672 (C4), 173.784 (C1).

Refinement top

The hydrogen atoms on N2 (HN2) and O3 (HO3) were refined isotropically. The remaining H atoms were included in calculated positions and treated as riding atoms. Aromatic C—H bond lengths were 0.93 Å and methylene C—H bond lengths were 0.97 Å, with Uiso(H) = 1.2 Ueq(C) in both cases.

Structure description top

Glycosylasparaginase is a key lysosomal enzyme in the catabolism of N-linked glycoproteins. The natural substrate for the enzyme is N4-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-L-asparagine. In a study of the enzyme-catalyzed reaction in which the structure of the amino acid part of the natural substrate was altered (and the sugar was unchanged), it was found that the binding sites on the enzyme for the sugar and the α-carboxyl group were sufficient for the enzyme to act on the substrate, with the α-amino group acting as an "anchor" in the binding site for the substrate (Risley et al., 2001). In a follow-up study, a series of N4-(4'-substituted phenyl)-L-asparagines were synthesized in which the structure of the amino acid part of the natural substrate was unchanged, but the sugar was substituted with para-substituted anilines. All of these β-anilides of asparagine were substrates for the enzyme (Du & Risley, 2003).

In order to better understand the role of the α-amino group in the binding to the enzyme, results from the two studies were used to design a series of N4-(4'-substituted phenyl)succinamic acids in which the structure of the amino acid part of the natural substrate was changed to succinamic acid (the α-amino group was replaced with a hydrogen) and the sugar part was substituted with para-substituted anilines. One of the substrate analogues synthesized was the title compound, with the atypical electron-withdrawing isocyano group that should make 4-isocyanoaniline a very good leaving group in the hydrolysis of the amide bond during the enzyme-catalyzed reaction. Initial studies of these analogues with the enzyme, however, indicated that they were neither substrates nor inhibitors. These initial studies would indicate that, for anilide substrates, the α-amino group is required for binding of the substrate to the active site of the enzyme, in contrast to the sugar substrates for which the α-amino group was not required.

The pair of molecules related by the inversion center at (1/2,1/2,0) are joined by two symmetry-equivalent O—H···O hydrogen bonds, as shown in Figure 2 and described in Table 1. The non-hydrogen atoms of the molecule are nearly planar, with the exception of those in the carboxylic acid group. A mean plane was fit to all of the non-hydrogen atoms except those of the carboxylic group; the maximum deviation of the fitted atoms is 0.270 (1) Å, for C10. The carbon of the carboxylic group, C11, lies 1.730 (2) Å from the mean plane.

For the structure of 4-isocyanoaniline see: Britton (1993). For details of the enzyme-catalysed reaction, see: Risley et al. (2001); Du & Risley (2003). For the synthetic procedures, see: Heinze & Jacob (2003); Kar & Argade (2002).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. View of the title compound. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Crystal packing diagram of the title compound showing hydrogen bonding.
N-(4-Isocyanophenyl)succinamic acid top
Crystal data top
C11H10N2O3F(000) = 456
Mr = 218.21Dx = 1.395 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54182 Å
Hall symbol: -P 2ybcCell parameters from 2647 reflections
a = 5.0974 (2) Åθ = 3.5–66.9°
b = 16.2774 (7) ŵ = 0.87 mm1
c = 12.5674 (6) ÅT = 100 K
β = 94.771 (4)°Prism, colourless
V = 1039.13 (8) Å30.42 × 0.09 × 0.08 mm
Z = 4
Data collection top
Agilent Xcalibur Atlas Gemini ultra
diffractometer
1839 independent reflections
Graphite monochromator1527 reflections with I > 2σ(I)
Detector resolution: 10.4419 pixels mm-1Rint = 0.035
ω scansθmax = 67.0°, θmin = 4.5°
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
h = 56
Tmin = 0.746, Tmax = 1k = 1919
7543 measured reflectionsl = 1414
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.096H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0476P)2 + 0.257P]
where P = (Fo2 + 2Fc2)/3
1839 reflections(Δ/σ)max < 0.001
153 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.25 e Å3
Crystal data top
C11H10N2O3V = 1039.13 (8) Å3
Mr = 218.21Z = 4
Monoclinic, P21/cCu Kα radiation
a = 5.0974 (2) ŵ = 0.87 mm1
b = 16.2774 (7) ÅT = 100 K
c = 12.5674 (6) Å0.42 × 0.09 × 0.08 mm
β = 94.771 (4)°
Data collection top
Agilent Xcalibur Atlas Gemini ultra
diffractometer
1839 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
1527 reflections with I > 2σ(I)
Tmin = 0.746, Tmax = 1Rint = 0.035
7543 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.096H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.21 e Å3
1839 reflectionsΔρmin = 0.25 e Å3
153 parameters
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
HN20.184 (4)0.6215 (11)0.6545 (15)0.028 (5)*
HO30.484 (5)0.4256 (16)0.9999 (19)0.064 (7)*
O30.3472 (2)0.40108 (7)0.95600 (10)0.0327 (3)
O20.2537 (2)0.53307 (7)0.92254 (10)0.0307 (3)
O10.2238 (2)0.48805 (7)0.66450 (9)0.0302 (3)
N20.0524 (3)0.59719 (8)0.63180 (11)0.0246 (3)
N10.4162 (3)0.77295 (8)0.31697 (11)0.0286 (3)
C40.0207 (3)0.71789 (10)0.52404 (13)0.0254 (4)
H40.15830.74040.55850.03*
C70.3901 (3)0.65037 (10)0.42199 (13)0.0261 (4)
H70.52850.62830.38750.031*
C20.2966 (3)0.72819 (10)0.39560 (12)0.0248 (4)
C60.2774 (3)0.60562 (10)0.49959 (13)0.0254 (4)
H60.3390.55310.5170.03*
C30.0902 (3)0.76253 (10)0.44606 (13)0.0268 (4)
H30.0280.81470.42750.032*
C80.0281 (3)0.52704 (10)0.68370 (13)0.0246 (4)
C90.1502 (3)0.49859 (10)0.76713 (13)0.0269 (4)
H9A0.31550.47930.73210.032*
H9B0.1880.54450.81270.032*
C50.0710 (3)0.63904 (9)0.55200 (12)0.0234 (3)
C110.2059 (3)0.46016 (10)0.90780 (13)0.0256 (4)
C10.5262 (4)0.80691 (11)0.25313 (15)0.0351 (4)
C100.0224 (3)0.43002 (10)0.83482 (14)0.0281 (4)
H10C0.15250.40560.87720.034*
H10D0.03850.38770.78840.034*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O30.0293 (7)0.0276 (6)0.0401 (7)0.0031 (5)0.0031 (5)0.0038 (5)
O20.0316 (6)0.0264 (6)0.0338 (7)0.0021 (5)0.0002 (5)0.0004 (5)
O10.0254 (6)0.0309 (6)0.0350 (7)0.0056 (5)0.0068 (5)0.0026 (5)
N20.0213 (7)0.0262 (7)0.0271 (7)0.0038 (6)0.0074 (6)0.0001 (6)
N10.0269 (7)0.0296 (7)0.0297 (8)0.0010 (6)0.0039 (6)0.0007 (6)
C40.0215 (8)0.0264 (8)0.0287 (9)0.0027 (6)0.0050 (7)0.0037 (6)
C70.0222 (8)0.0299 (8)0.0268 (9)0.0000 (6)0.0049 (7)0.0059 (7)
C20.0238 (8)0.0273 (8)0.0235 (8)0.0026 (6)0.0038 (7)0.0006 (6)
C60.0255 (8)0.0234 (8)0.0277 (8)0.0028 (6)0.0042 (7)0.0025 (6)
C30.0248 (8)0.0234 (8)0.0323 (9)0.0012 (6)0.0032 (7)0.0002 (7)
C80.0213 (8)0.0263 (8)0.0259 (8)0.0012 (6)0.0002 (6)0.0029 (6)
C90.0226 (8)0.0309 (9)0.0275 (9)0.0015 (7)0.0035 (7)0.0018 (7)
C50.0219 (8)0.0247 (8)0.0234 (8)0.0010 (6)0.0013 (6)0.0031 (6)
C110.0252 (8)0.0278 (9)0.0248 (9)0.0008 (7)0.0083 (7)0.0029 (7)
C10.0313 (9)0.0378 (10)0.0365 (10)0.0023 (8)0.0054 (8)0.0037 (8)
C100.0266 (9)0.0282 (8)0.0302 (9)0.0035 (7)0.0066 (7)0.0007 (7)
Geometric parameters (Å, º) top
O3—C111.318 (2)C7—C21.384 (2)
O3—HO30.94 (3)C7—H70.93
O2—C111.2226 (19)C2—C31.390 (2)
O1—C81.2235 (19)C6—C51.397 (2)
N2—C81.361 (2)C6—H60.93
N2—C51.404 (2)C3—H30.93
N2—HN20.85 (2)C8—C91.516 (2)
N1—C11.157 (2)C9—C101.517 (2)
N1—C21.407 (2)C9—H9A0.97
C4—C31.378 (2)C9—H9B0.97
C4—C51.401 (2)C11—C101.503 (2)
C4—H40.93C10—H10C0.97
C7—C61.380 (2)C10—H10D0.97
C11—O3—HO3108.1 (15)O1—C8—C9121.58 (15)
C8—N2—C5127.90 (14)N2—C8—C9114.42 (14)
C8—N2—HN2116.4 (12)C8—C9—C10111.00 (13)
C5—N2—HN2115.4 (12)C8—C9—H9A109.4
C1—N1—C2176.27 (17)C10—C9—H9A109.4
C3—C4—C5120.89 (14)C8—C9—H9B109.4
C3—C4—H4119.6C10—C9—H9B109.4
C5—C4—H4119.6H9A—C9—H9B108
C6—C7—C2119.82 (14)C6—C5—C4119.16 (14)
C6—C7—H7120.1C6—C5—N2123.20 (14)
C2—C7—H7120.1C4—C5—N2117.64 (13)
C7—C2—C3121.15 (15)O2—C11—O3122.96 (15)
C7—C2—N1118.79 (14)O2—C11—C10122.95 (15)
C3—C2—N1120.06 (14)O3—C11—C10114.08 (14)
C7—C6—C5120.10 (15)C11—C10—C9112.13 (13)
C7—C6—H6119.9C11—C10—H10C109.2
C5—C6—H6119.9C9—C10—H10C109.2
C4—C3—C2118.89 (15)C11—C10—H10D109.2
C4—C3—H3120.6C9—C10—H10D109.2
C2—C3—H3120.6H10C—C10—H10D107.9
O1—C8—N2123.98 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—HO3···O2i0.94 (3)1.72 (3)2.6646 (17)177 (2)
Symmetry code: (i) x+1, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC11H10N2O3
Mr218.21
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)5.0974 (2), 16.2774 (7), 12.5674 (6)
β (°) 94.771 (4)
V3)1039.13 (8)
Z4
Radiation typeCu Kα
µ (mm1)0.87
Crystal size (mm)0.42 × 0.09 × 0.08
Data collection
DiffractometerAgilent Xcalibur Atlas Gemini ultra
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2011)
Tmin, Tmax0.746, 1
No. of measured, independent and
observed [I > 2σ(I)] reflections
7543, 1839, 1527
Rint0.035
(sin θ/λ)max1)0.597
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.096, 1.07
No. of reflections1839
No. of parameters153
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.21, 0.25

Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006), WinGX publication routines (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—HO3···O2i0.94 (3)1.72 (3)2.6646 (17)177 (2)
Symmetry code: (i) x+1, y+1, z+2.
 

Acknowledgements

This work was supported in part by funds provided by the University of North Carolina at Charlotte. Support for Research Experience for Undergraduates (REU) participant LEB was provided by the National Science Foundation, award number CHE-0851797. The assistance of Mya Aun in the preparation of the manuscript is gratefully acknowledged.

References

First citationAgilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.  Google Scholar
First citationBritton, D. (1993). J. Crystallogr. Spectrosc. Res. 23, 689–690.  CrossRef CAS Web of Science Google Scholar
First citationDu, W. & Risley, J. M. (2003). Org. Biomol. Chem. 1, 1900–1905.  Web of Science CrossRef PubMed CAS Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
First citationHeinze, K. & Jacob, V. (2003). Eur. J. Inorg. Chem. pp. 3918–3923.  Web of Science CrossRef Google Scholar
First citationKar, A. & Argade, N. P. (2002). Synthesis, pp. 221–224.  CrossRef Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationRisley, J. M., Huang, D. H., Kaylor, J. J., Malik, J. J., Xia, Y. Q. & York, W. M. (2001). Arch. Biochem. Biophys. 391, 165–170.  Web of Science CrossRef PubMed CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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