Cotton Marcia S, Rupnik Kresimir, Broach Robyn B, Hu Yilin, Fay Aaron W, Ribbe Markus W, Hales Brian J
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
J Am Chem Soc. 2009 Apr 8;131(13):4558-9. doi: 10.1021/ja807525m.
NifZ is a member of a series of proteins associated with the maturation of the nitrogenase MoFe protein. An MCD spectroscopic study was undertaken on the Delta nifB Delta nifZ MoFe protein generated in the absence of both NifZ and NifB (deletion of NifB generates an apo-MoFe protein lacking the FeMo cofactor). Results presented here show that, in the absence of NifZ, only one of the two P-clusters of the MoFe protein is matured to the ultimate [8Fe-7S] structure. The other P-cluster site in the protein contains a [4Fe-4S] cluster pair, representing a P-cluster precursor that is electronically identical to the analogous clusters observed in the Delta nifH MoFe protein. These results suggest that the MoFe protein is synthesized in a stepwise fashion where NifZ is specifically required for the formation of the second P-cluster.
NifZ是与固氮酶钼铁蛋白成熟相关的一系列蛋白质中的一员。对在缺乏NifZ和NifB的情况下产生的ΔnifBΔnifZ钼铁蛋白进行了MCD光谱研究（删除NifB会产生缺乏铁钼辅因子的脱辅基钼铁蛋白）。此处给出的结果表明，在没有NifZ的情况下，钼铁蛋白的两个P簇中只有一个成熟为最终的[8Fe-7S]结构。该蛋白中的另一个P簇位点包含一对[4Fe-4S]簇，代表一种P簇前体，其电子结构与在ΔnifH钼铁蛋白中观察到的类似簇相同。这些结果表明，钼铁蛋白是以逐步方式合成的，其中NifZ是形成第二个P簇所特需的。
