Premium
EPR study of 1Asp–3Cys ligated 4Fe–4S iron–sulfur cluster in NB‐protein (BchN–BchB) of a dark‐operative protochlorophyllide reductase complex
Author(s) -
Kondo Toru,
Nomata Jiro,
Fujita Yuichi,
Itoh Shigeru
Publication year - 2011
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/j.febslet.2010.11.044
Subject(s) - protochlorophyllide , electron paramagnetic resonance , iron–sulfur cluster , oxidoreductase , nitrogenase , chemistry , enzyme , sulfur , cluster (spacecraft) , biochemistry , crystallography , nuclear magnetic resonance , physics , organic chemistry , nitrogen fixation , computer science , nitrogen , programming language
Dark‐operative protochlorophyllide oxidoreductase, a nitrogenase‐like enzyme, contains two [4Fe–4S] clusters, one in the L‐protein ((BchL) 2 ) and the other in the NB‐protein ((BchN–BchB) 2 ). The reduced NB‐cluster in the NB‐protein, which is ligated by 1Asp/3Cys residues, showed a broad S = 3/2 electron paramagnetic resonance signal that is rather rare in [4Fe–4S] clusters. A 4Cys‐ligated NB‐cluster in the mutated variant BchB–D36C protein, in which the Asp36 was replaced by a Cys, gave a rhombic normal S = 1/2 signal and lost the catalytic activity. The results suggest that Asp36 contributes to the low redox potential necessary to reduce protochlorophyllide.