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Spontaneous spectral changes of the reduced cytochrome bd
Author(s) -
Azarkitalya,
Borisov Vitaliy,
Konstantinov Alexander A
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)01196-4
Subject(s) - heme , chemistry , azotobacter vinelandii , cytochrome , ligand (biochemistry) , bacillus subtilis , hemeprotein , absorption (acoustics) , heme a , photochemistry , biochemistry , enzyme , biology , bacteria , receptor , organic chemistry , nitrogen fixation , nitrogenase , physics , acoustics , nitrogen , genetics
Reduction of the membrane‐bound cytochrome bd from Bacillus subtilis , Escherichia coli and Azotobacter vinelandii as well as of the purified enzyme from E. coli was followed by secondary absorption changes on a time scale of tens of minutes. The difference absorption spectra of these changes resembled those induced by CO binding with heme d 2+ indicating interaction of the heme with an endogenous π‐acceptor ligand. The spontaneous spectral changes were prevented and reversed by CO binding with the reduced cytochrome bd . Bonding of heme d iron to an endogenous protein ligand at the sixth axial position upon reduction is proposed and several possible mechanisms of such a process are considered.