ISSN:
0887-3585
Keywords:
myoglobin
;
nitric oxide
;
ligand binding
;
X-ray crystallography
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
The structure of the ferrous nitric oxide form of native sperm whale myoglobin has been determined by X-ray crystallography to 1.7 Å resolution. The nitric oxide ligand is bent with respect to the heme plane: the Fe-N-O angle is 112°. This angle is smaller than those observed in model compounds and in lupin leghemoglobin. The exact angle appears to be influenced by the strength of the proximal bond and hydrogen bonding interactions between the distal histidine and the bound ligand. Specifically, the Nε atom of histidine64 is located 2.8 Å away from the nitrogen atom of the bound ligand, implying electrostatic stabilization of the FeNO complex. This interpretation is supported by mutagenesis studies. When histidine64 is replaced with apolar amino acids, the rate of nitric oxide dissociation from myoglobin increases tenfold. Proteins 30:352-356, 1998. © 1998 Wiley-Liss, Inc.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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