几种革兰氏阳性菌和革兰氏阴性菌中铁氧化还原蛋白：NAD(+)氧化还原酶活性的出现及其离子特异性
Occurrence of ferredoxin:NAD(+) oxidoreductase activity and its ion specificity in several Gram-positive and Gram-negative bacteria.
作者信息
Hess Verena, Gallegos Rene, Jones J Andrew, Barquera Blanca, Malamy Michael H, Müller Volker
机构信息
Molecular Microbiology and Bioenergetics, Goethe University Frankfurt , Frankfurt am Main , Germany.
Department of Molecular Biology and Microbiology, Tufts University, School of Medicine and Sackler School of Graduate Biomedical Sciences , Boston, Masachusetts , United States.
出版信息
PeerJ. 2016 Jan 11;4:e1515. doi: 10.7717/peerj.1515. eCollection 2016.
A ferredoxin:NAD(+) oxidoreductase was recently discovered as a redox-driven ion pump in the anaerobic, acetogenic bacterium Acetobacterium woodii. The enzyme is assumed to be encoded by the rnf genes. Since these genes are present in the genomes of many bacteria, we tested for ferredoxin:NAD(+) oxidoreductase activity in cytoplasmic membranes from several different Gram-positive and Gram-negative bacteria that have annotated rnf genes. We found this activity in Clostridium tetanomorphum, Clostridium ljungdahlii, Bacteroides fragilis, and Vibrio cholerae but not in Escherichia coli and Rhodobacter capsulatus. As in A. woodii, the activity was Na(+)-dependent in C. tetanomorphum and B. fragilis but Na(+)-independent in C. ljungdahlii and V. cholerae. We deleted the rnf genes from B. fragilis and demonstrated that the mutant has greatly reduced ferredoxin:NAD(+) oxidoreductase activity. This is the first genetic proof that the rnf genes indeed encode the reduced ferredoxin:NAD(+) oxidoreductase activity.
最近，在厌氧产乙酸细菌伍氏醋酸杆菌中发现了一种铁氧化还原蛋白：NAD(+)氧化还原酶，它是一种由氧化还原驱动的离子泵。该酶被认为是由rnf基因编码的。由于这些基因存在于许多细菌的基因组中，我们检测了几种已注释rnf基因的不同革兰氏阳性和革兰氏阴性细菌细胞质膜中的铁氧化还原蛋白：NAD(+)氧化还原酶活性。我们在破伤风梭状芽孢杆菌、李氏梭菌、脆弱拟杆菌和霍乱弧菌中发现了这种活性，但在大肠杆菌和荚膜红细菌中未发现。与伍氏醋酸杆菌一样，破伤风梭状芽孢杆菌和脆弱拟杆菌中的活性依赖于Na(+)，而李氏梭菌和霍乱弧菌中的活性不依赖于Na(+)。我们从脆弱拟杆菌中删除了rnf基因，并证明该突变体的铁氧化还原蛋白：NAD(+)氧化还原酶活性大大降低。这是rnf基因确实编码还原型铁氧化还原蛋白：NAD(+)氧化还原酶活性的首个遗传学证据。
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