Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; State Key Laboratory of Microbial Technology, Shandong University, Jinan, People’s Republic of
J Bacteriol. 2010 Oct;192(19):5115-23. doi: 10.1128/JB.00612-10. Epub 2010 Jul 30.
It was recently found that the cytoplasmic butyryl-coenzyme A (butyryl-CoA) dehydrogenase-EtfAB complex from Clostridium kluyveri couples the exergonic reduction of crotonyl-CoA to butyryl-CoA with NADH and the endergonic reduction of ferredoxin with NADH via flavin-based electron bifurcation. We report here on a second cytoplasmic enzyme complex in C. kluyveri capable of energetic coupling via this novel mechanism. It was found that the purified iron-sulfur flavoprotein complex NfnAB couples the exergonic reduction of NADP+ with reduced ferredoxin (Fdred) and the endergonic reduction of NADP+ with NADH in a reversible reaction: Fdred2-+NADH+2 NADP++H+=Fdox+NAD++2 NADPH. The role of this energy-converting enzyme complex in the ethanol-acetate fermentation of C. kluyveri is discussed.
最近发现，来自克氏梭菌的细胞质丁酰基辅酶 A（丁酰-CoA）脱氢酶-EtfAB 复合物通过黄素基电子分叉将顺丁烯酰辅酶 A与 NADH 的放能还原与铁氧还蛋白与 NADH 的吸能还原偶联。我们在这里报告克氏梭菌中第二个能够通过这种新机制进行能量偶联的细胞质酶复合物。结果发现，纯化的铁硫黄素蛋白复合物 NfnAB 在可逆反应中偶联 NADP+的放能还原与还原型铁氧还蛋白（Fdred）以及 NADP+的吸能还原与 NADH：Fdred2-+NADH+2 NADP++H+=Fdox+NAD++2 NADPH。讨论了该能量转换酶复合物在克氏梭菌的乙醇-乙酸发酵中的作用。
