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Structure of Insulin: Results of joint neutron and X-ray refinement

Abstract

Neutron diffraction data for porcine 2Zn insulin were collected to 2.2 A resolution from a single crystal deuterated by slow exchange of mother liquor. A joint neutron/X-ray restrained-least-squares refinement was undertaken using the neutron data, as well as the 1.5 A resolution X-ray data collected previously. The final R factors were 0.182 for the X-ray data and 0.191 for the neutron data. Resulting atomic coordinates were compared with the initial X-ray model, showing a total r.m.s. shift of 0.36 A for the protein and 0.6 A for the solvent. Protonation of a number of individual amino acids was investigated by analysis of the neutron maps. No D atoms were found between the carboxylates of Glu B13 which make an intermolecular contact, suggesting nonbonded interaction rather than the predicted hydrogen bond. Amide hydrogen exchange was investigated in a refinement of their atomic occupancies. Regions of unexchanged amide groups were found in the center of the B helices. The results of this study emphasize the limited amount of information available in neutron diffraction studies of proteins at resolution lower than 2 A.
Publication Date:
Feb 01, 1989
Product Type:
Journal Article
Reference Number:
DENM-89-000247; EDB-89-067007
Resource Relation:
Journal Name: Acta Crystallogr. Sect. B: Struct. Sci.; (Denmark); Journal Volume: 45:1
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 74 ATOMIC AND MOLECULAR PHYSICS; INSULIN; CRYSTAL STRUCTURE; MOLECULAR STRUCTURE; DEUTERATION; EXPERIMENTAL DATA; INTERMOLECULAR FORCES; LEAST SQUARE FIT; MONOCRYSTALS; NEUTRON DIFFRACTION; PROTEINS; SOLVENTS; X-RAY DIFFRACTION; CHEMICAL REACTIONS; COHERENT SCATTERING; CRYSTALS; DATA; DIFFRACTION; HORMONES; INFORMATION; MAXIMUM-LIKELIHOOD FIT; NUMERICAL DATA; NUMERICAL SOLUTION; ORGANIC COMPOUNDS; PEPTIDE HORMONES; SCATTERING; 656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-); 640302 - Atomic, Molecular & Chemical Physics- Atomic & Molecular Properties & Theory
OSTI ID:
6140825
Research Organizations:
National Bureau of Standards, Gaithersburg, MD (USA). Center for Chemical Physics; National Institutes of Health, Bethesda, MD (USA). Lab. of Molecular Biology; York Univ. (UK). Dept. of Chemistry
Country of Origin:
Denmark
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: ASBSD
Submitting Site:
DK
Size:
Pages: 99-107
Announcement Date:

Citation Formats

Wlodawer, A, Savage, H, and Dodson, G. Structure of Insulin: Results of joint neutron and X-ray refinement. Denmark: N. p., 1989. Web. doi:10.1107/S0108768188011012.
Wlodawer, A, Savage, H, & Dodson, G. Structure of Insulin: Results of joint neutron and X-ray refinement. Denmark. doi:10.1107/S0108768188011012.
Wlodawer, A, Savage, H, and Dodson, G. 1989. "Structure of Insulin: Results of joint neutron and X-ray refinement." Denmark. doi:10.1107/S0108768188011012. https://www.osti.gov/servlets/purl/10.1107/S0108768188011012.
@misc{etde_6140825,
title = {Structure of Insulin: Results of joint neutron and X-ray refinement}
author = {Wlodawer, A, Savage, H, and Dodson, G}
abstractNote = {Neutron diffraction data for porcine 2Zn insulin were collected to 2.2 A resolution from a single crystal deuterated by slow exchange of mother liquor. A joint neutron/X-ray restrained-least-squares refinement was undertaken using the neutron data, as well as the 1.5 A resolution X-ray data collected previously. The final R factors were 0.182 for the X-ray data and 0.191 for the neutron data. Resulting atomic coordinates were compared with the initial X-ray model, showing a total r.m.s. shift of 0.36 A for the protein and 0.6 A for the solvent. Protonation of a number of individual amino acids was investigated by analysis of the neutron maps. No D atoms were found between the carboxylates of Glu B13 which make an intermolecular contact, suggesting nonbonded interaction rather than the predicted hydrogen bond. Amide hydrogen exchange was investigated in a refinement of their atomic occupancies. Regions of unexchanged amide groups were found in the center of the B helices. The results of this study emphasize the limited amount of information available in neutron diffraction studies of proteins at resolution lower than 2 A.}
doi = {10.1107/S0108768188011012}
journal = {Acta Crystallogr. Sect. B: Struct. Sci.; (Denmark)}
volume = {45:1}
journal type = {AC}
place = {Denmark}
year = {1989}
month = {Feb}
}