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Evidence for function overlapping of CymA and the cytochrome bc 1 complex in the S hewanella oneidensis nitrate and nitrite respiration
Author(s) -
Fu Huihui,
Jin Miao,
Ju Lili,
Mao Yinting,
Gao Haichun
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12457
Subject(s) - nitrite , cytochrome , biology , anaerobic respiration , biochemistry , nitrate , electron transport chain , shewanella oneidensis , respiration , cellular respiration , anaerobic exercise , genetics , enzyme , mitochondrion , physiology , anatomy , ecology , bacteria
Summary S hewanella oneidensis is an important model organism for its versatility of anaerobic respiration. CymA , a cytoplasmic membrane‐bound tetraheme c ‐type cytochrome, plays a central role in anaerobic respiration by transferring electrons from the quinone pool to a variety of terminal reductases. Although loss of CymA results in defect in respiration of many electron acceptors ( EAs ), a significant share of the capacity remains in general. In this study, we adopted a transposon random mutagenesis method in a cymA null mutant to identify substituent(s) of CymA with respect to nitrite and nitrate respiration. A total of 87 insertion mutants, whose ability to reduce nitrite was further impaired, were obtained. Among the interrupted genes, the pet ABC operon appeared to be the most likely candidate given the involvement of the cytochrome bc 1 complex that it encodes in electron transport. Subsequent analyses not only confirmed that the complex and CymA were indeed functionally overlapping in nitrate/nitrite respiration but also revealed that both proteins were able to draw electrons from ubiquinone and menaquinone. Furthermore, we found that expression of the bc 1 complex was affected by oxygen but not nitrate or nitrite and by global regulators ArcA and Crp in an indirect manner.