Schmitz O, Gurke J, Bothe H
Botanical Institute, The University of Cologne, Gyrhofstr. 15, D-50923, Köln, Germany.
FEMS Microbiol Lett. 2001 Feb 5;195(1):97-102. doi: 10.1111/j.1574-6968.2001.tb10504.x.
Pyruvate:ferredoxin (flavodoxin) oxidoreductase (PFO, EC 1.2.7.1) catalyses the oxidative cleavage of pyruvate and coenzyme A to acetylcoenzyme A and CO2 with the simultaneous reduction of ferredoxin or flavodoxin. PFO occurs in anaerobes and in some aerobic archaea and bacteria. For cyanobacteria, activity measurements indicated the occurrence of PFO in heterocystous forms. The completely sequenced genomes of the unicellular Synechocystis sp. PCC 6803 and the heterocystous Anabaena sp. PCC 7120 and Nostoc punctiforme revealed the existence of one PFO (encoded by nifJ) in Synechocystis 6803 and N. punctiforme but two different PFOs, encoded by nifJ1 and nifJ2, in Anabaena. Sequence comparison now indicates that all cyanobacterial PFOs are more closely related to those of anaerobes than to those of aerobes. Reverse transcription-polymerase chain reaction (RT-PCR) experiments show that nifJ is transcribed in the presence of saturating iron concentrations in aerobically grown cells of the unicellular Synechococcus sp. PCC 6301 and Synechocystis 6803. Both nifJ genes are transcribed in aerobically grown Anabaena 7120. These findings are corroborated by luciferase reporter gene analysis of nifJ in Synechococcus sp. PCC 7942. The occurrence of PFO in these cyanobacteria is enigmatic.
铁氧化还原蛋白（黄素氧化还原蛋白）氧化还原酶（PFO，EC 1.2.7.1）催化丙酮酸和辅酶A氧化裂解为乙酰辅酶A和二氧化碳，同时使铁氧化还原蛋白或黄素氧化还原蛋白还原。PFO存在于厌氧菌以及一些好氧古菌和细菌中。对于蓝细菌，活性测定表明异形胞形式中存在PFO。单细胞集胞蓝细菌属PCC 6803、异形胞鱼腥藻属PCC 7120和点状念珠藻的全基因组测序显示，集胞蓝细菌6803和点状念珠藻中有一个PFO（由nifJ编码），但鱼腥藻中有两个不同的PFO，分别由nifJ1和nifJ2编码。序列比较表明，所有蓝细菌的PFO与厌氧菌的PFO比与需氧菌的PFO关系更密切。逆转录-聚合酶链反应（RT-PCR）实验表明，在单细胞聚球藻属PCC 6301和集胞蓝细菌6803需氧生长的细胞中，当铁浓度饱和时nifJ会转录。在需氧生长的鱼腥藻7120中，两个nifJ基因都会转录。聚球藻属PCC 7942中nifJ的荧光素酶报告基因分析证实了这些发现。这些蓝细菌中PFO的存在令人费解。
