Hillmann Falk, Riebe Oliver, Fischer Ralf-Jörg, Mot Augustin, Caranto Jonathan D, Kurtz Donald M, Bahl Hubert
Division of Microbiology, Institute of Biological Sciences, University of Rostock, Rostock, Germany.
FEBS Lett. 2009 Jan 5;583(1):241-5. doi: 10.1016/j.febslet.2008.12.004. Epub 2008 Dec 11.
Two flavo-diiron proteins (FDPs), FprA1 and FprA2, are up-regulated when the strictly anaerobic solvent producer, Clostridium acetobutylicum, is exposed to dioxygen. These two FDPs were purified following heterologous overexpression in Escherichia coli as N-terminal Strep-tag fusion proteins. The recombinant FprA1 and FprA2 were found to be homodimeric and homotetrameric, respectively, and both FDPs functioned as terminal components of NADH oxidases (NADH:O(2) oxidoreductases) when using C. acetobutylicum NADH:rubredoxin oxidoreductase (NROR) and rubredoxin (Rd) as electron transport intermediaries. Both FDPs catalyzed the four-electron reduction of molecular oxygen to water with similar specific activities. The results are consistent with these FDPs functioning as efficient scavengers of intracellular dioxygen under aerobic or microoxic growth conditions.
当严格厌氧的溶剂产生菌丙酮丁醇梭菌暴露于氧气时，两种黄素二铁蛋白（FDPs），即FprA1和FprA2会被上调表达。这两种FDPs在大肠杆菌中作为N端链霉亲和标签融合蛋白进行异源过表达后得以纯化。发现重组FprA1和FprA2分别为同型二聚体和同型四聚体，并且当使用丙酮丁醇梭菌的NADH：铁氧化还原蛋白氧化还原酶（NROR）和铁氧化还原蛋白（Rd）作为电子传递中间体时，这两种FDPs均作为NADH氧化酶（NADH：O₂氧化还原酶）的末端组分发挥作用。两种FDPs都以相似的比活性催化分子氧的四电子还原生成水。这些结果与这些FDPs在需氧或微氧生长条件下作为细胞内氧气的有效清除剂的功能一致。
