(IUCr) Crystallography Journals Online checkcif report

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Acta Cryst. (2004). E60, o720-o721 [ doi:10.1107/S1600536804007299 ]

A short depsipeptide: tert-butoxycarbonyl-L-alanyl-L-lactic acid benzyl ester (Boc-L-Ala-L-Lac-OBzl)

H. Oku, T. Suda, K. Yamada and R. Katakai

Key indicators

Single-crystal X-ray study
T = 173 K
Mean (C-C) = 0.009 Å
R factor = 0.070
wR factor = 0.182
Data-to-parameter ratio = 9.1

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.92

Author Response: This is due to the data collection by rotation around a spindle axis on our image-plate system.

PLAT201_ALERT_2_A Isotropic non-H Atoms in Main Residue(s) .......         12

Author Response: Because of the limited numbers of observed reflections. Even at the low temperature condition (173 K), diffractions from the crystal of (I) were too weak to collect enough numbers. Therefore only main-cain atoms were refefined anisotropically.


Alert level C
REFLT03_ALERT_1_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           68.15
           From the CIF: _diffrn_reflns_theta_full           0.00
           From the CIF: _reflns_number_total               1747
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1905
           Completeness (_total/calc)             91.71%

Author Response: All the Friedel pairs have been averaged during the refinement process.

PLAT022_ALERT_3_C Ratio Unique / Expected Reflections too Low ....       0.92       
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....       C101

Author Response: It is due to the difference of thermal mobility. The atoms located at chain-ends and amino-acid side chains often show higer U(eq) compared with the atoms located inside of the molecule.

PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          9

Author Response: The chain end atoms (-OEt) often show lower bond precision due to their higher thermal mobility compared with the atoms located inside of the chain.


Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           68.15
           From the CIF: _reflns_number_total               1747
           Count of symmetry unique reflns         1905
           Completeness (_total/calc)             91.71%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present           no

Author Response: All the Friedel pairs have been averaged during the refinement process.


   2 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion