Crystal structure and functional analysis of 2-oxacid : ferredoxin oxidoreductase

点击翻译按钮获取中文摘要

2-Oxoacid : ferredoxin oxidoreductases (OFORs) from Sulfolobus sp. Strain 7 and from Aeropyrum were used for making crystals for X-ray crystallography. However, some of them formed crystals which were found to diffract X-ray with very low resolution.Five possible active site residues that recognize 2-oxoacid in Sulfolobus OFOR were selected from the comparison of OFORs from Sulfolobus and other sources in terms of teriary structure and amino acid alignment. To eleuidate the role of these residues, they were subjected to site-directed mutagenesis to obtain a serious of variant enzymes. Arg344 and Thr353 of the subunit-a were essential and important, respectively. Lys49 and Leu123 of the subunit-b were responsible for the recognition of 2-oxoglutarate and pyruvate, respectively. A GXXGXG motif, supposed to bind to CoA, was examined. Each of the Gly was essential for enzyme activity, suggesting the importance of the motif.During the course of OFOR research, an enzyme capable of catalyzing both decarboxylation and oxidation of indolepyruvate has been discovered. The reaction was independent of ferredoxin or CoA, and its final product was indoleacetic acid. The enzyme was a molybdo-flavo-iron-sulfur protein with biotin.