大肠杆菌喹啉酸合成酶确实含有一个[4Fe-4S]簇。

Escherichia coli quinolinate synthetase does indeed harbor a [4Fe-4S] cluster.

作者信息

Cicchillo Robert M, Tu Loretta, Stromberg Jeffrey A, Hoffart Lee M, Krebs Carsten, Booker Squire J

机构信息

Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, 16802, USA.

出版信息

J Am Chem Soc. 2005 May 25;127(20):7310-1. doi: 10.1021/ja051369x.

DOI:10.1021/ja051369x

PMID:15898769

Abstract

Quinolinic acid is an intermediate in the biosynthesis of nicotinamide-containing redox cofactors. The ultimate step in the formation of quinolinic acid in prokaryotes is the condensation of iminosuccinate and dihydroxyacetone phosphate, which is catalyzed by the product of the nadA gene in Escherichia coli. A combination of UV-vis, Mössbauer, and EPR spectroscopies, along with analytical methods for the determination of iron and sulfide, demonstrates for the first time that anaerobically purified quinolinate synthetase (NadA) from E. coli contains one [4Fe-4S] cluster per polypeptide. The protein is active, catalyzing the formation of quinolinic acid with a Vmax [ET]-1 of 0.01 s-1.

摘要

喹啉酸是含烟酰胺的氧化还原辅因子生物合成过程中的一种中间体。原核生物中喹啉酸形成的最后一步是亚氨基琥珀酸和磷酸二羟丙酮的缩合反应，该反应由大肠杆菌中nadA基因的产物催化。紫外可见光谱、穆斯堡尔光谱和电子顺磁共振光谱相结合，以及铁和硫化物的分析测定方法，首次证明了从大肠杆菌中厌氧纯化得到的喹啉酸合成酶（NadA）每条多肽链含有一个[4Fe-4S]簇。该蛋白质具有活性，催化喹啉酸的形成，最大反应速度Vmax [ET]-1为0.01 s-1。