Cheng, X., Schoenborn, B. P. (July 1991) Neutron Diffraction Study of Carbonmonoxymyoglobin. Journal of Molecular Biology, 220 (2). pp. 381-400. ISSN 0022-2836 (Print)0022-2836 (Linking)
Abstract
Neutron diffraction data from a crystal of carbonmonoxymyoglobin were refined by PROLSQ, a modern restrained least-squares procedure in reciprocal space, in conjunction with a solvent analysis technique, to a final R-factor of 11.3%. The ligand CO occupies two sites and its binding conformations are distorted from the linear conformation. The N.epsilon. atom of the distal histidine residue is deprotonated (not deuterated), and a water molecule is bound to the N.delta. atom of the distal histidine. The side-chain of Lys56 (D6) exists in two alternative charge-binding sites. His24 (B5) and His119 (GH1) share a hydrogen atom. His12 (A10) and His36 (C1) are deprotonated. The deprotonated imidazole ring of His12 (A10) may act as a hydrogen-bond acceptor. The heme group is planar within 0.09 .ANG. root-mean-square (r.m.s.) deviation from planarity. The solvent environments for the two propionic acid groups are different. The side-chain of Arg45 (CD3) forms hydrogen bonds with the side chain of Asp60 (E3) and one of the two propionic acid groups. An average N-2H...O angle in helical regions is 147(.+-. 11).degree.. Eleven main-chain amide hydrogen atoms from hydrophobic residues do not exchange with deuterium. The overall atomic occupancy factors for the main-chain and side-chain atoms are quite uniform, at 0.97 (.+-. 0.07) and 0.93(.+-. 0.10), respectively, as shown by an occupancy analysis made at the end of the refinement procedure.
| Item Type: | Paper |
|---|---|
| Uncontrolled Keywords: | Amino Acid Sequence Binding Sites Carbon Monoxide/metabolism Crystallization Fourier Analysis Heme/metabolism Mathematics Models, Molecular Molecular Sequence Data Myoglobin/*chemistry/metabolism Neutrons Protein Conformation Scattering, Radiation |
| Subjects: | organs, tissues, organelles, cell types and functions > organs types and functions > metabolism |
| CSHL Authors: | |
| Communities: | CSHL labs |
| Depositing User: | Matt Covey |
| Date: | 20 July 1991 |
| Date Deposited: | 22 Dec 2015 17:15 |
| Last Modified: | 22 Dec 2015 17:15 |
| Related URLs: | |
| URI: | https://repository.cshl.edu/id/eprint/32114 |
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