Cyanide and azide behave in a similar fashion versus cuprozinc-superoxide dismutase.
The 1H NMR spectra of the cyanide adduct of Cu2Co2-superoxide dismutase have been remeasured at pH 7.5. The exchange rate of CN- is slow on the NMR time scale. The correlation with the spectrum of the unligated enzyme has been established through saturation-transfer techniques of the system in which 50% of the cyanide adduct is formed and through comparison with the spectrum of a Cu2Co2-superoxide dismutase-CN- sample in which the histidines have been deuterium labeled at the position epsilon 1. The similarities between the spectra of the CN- and N-3 derivatives are stressed, in particular with respect to the removal from copper coordination of the same histidine, assigned as His-46.
Banci
L
L
Department of Chemistry, University of Florence, Italy.
Bertini
I
I
Luchinat
C
C
Scozzafava
A
A
D000818:Animals; D001386:Azides / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D003486:Cyanides / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology; D006639:Histidine; D006801:Humans; D008099:Liver / Q000201:enzymology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*
D001386:Azides; D003486:Cyanides; D011994:Recombinant Proteins; D006639:Histidine; D013482:Superoxide Dismutase