ISSN:
1432-1327
Keywords:
Key words Heme protein
;
Nuclear magnetic resonance
;
Paramagnetic shifts
;
Axial ligand
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract The different paramagnetic shifts of the four methyl groups in ferriheme proteins have been described as being due to the effect of the axial ligand nodal plane orientation. An equation, heuristically found and theoretically explained, describing the relation between contact and pseudocontact shifts and the position of the axial ligand(s) has been derived for bis-histidine ferriheme proteins and for cyanide-histidine ferriheme proteins. The values of the heuristic parameters contained in the equations were found by fitting the shifts of bovine cytochrome b 5 and several bis-histidine cytochromes c 3 and histidine-cyanide systems. The agreement between the observed and the calculated shifts was found to be good. Therefore, by taking advantage of this study, information on the position of the axial ligands, that can be used as a constraint for structure determination, can be obtained from the shifts of the methyl protons.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007750050337
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