@article{mbs:/content/journal/micro/10.1099/mic.0.000285, author = "Wei, Hehong and Dai, Jingcheng and Xia, Ming and Romine, Margaret F. and Shi, Liang and Beliav, Alex and Tiedje, James M. and Nealson, Kenneth H. and Fredrickson, James K. and Zhou, Jizhong and Qiu, Dongru", title = "Functional roles of CymA and NapC in reduction of nitrate and nitrite by Shewanella putrefaciens W3-18-1", journal= "Microbiology", year = "2016", volume = "162", number = "6", pages = "930-941", doi = "https://doi.org/10.1099/mic.0.000285", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000285", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "specificity", keywords = "electron transfer", keywords = "tetraheme cytochromes", keywords = "nitrite reduction", keywords = "Nitrate reduction", keywords = "Shewanella putrefaciens", abstract = " Shewanella putrefaciens W3-18-1 harbours two periplasmic nitrate reductase (Nap) gene clusters, NapC-associated nap-alpha (napEDABC) and CymA-dependent nap-beta (napDAGHB), for dissimilatory nitrate respiration. CymA is a member of the NapC/NirT quinol dehydrogenase family and acts as a hub to support different respiratory pathways, including those on iron [Fe(III)] and manganese [Mn(III, IV)] (hydr)oxide, nitrate, nitrite, fumarate and arsenate in Shewanella strains. However, in our analysis it was shown that another NapC/NirT family protein, NapC, was only involved in nitrate reduction, although both CymA and NapC can transfer quinol-derived electrons to a periplasmic terminal reductase or an electron acceptor. Furthermore, our results showed that NapC could only interact specifically with the Nap-alpha nitrate reductase while CymA could interact promiscuously with Nap-alpha, Nap-beta and the NrfA nitrite reductase for nitrate and nitrite reduction. To further explore the difference in specificity, site-directed mutagenesis on both CymA and NapC was conducted and the phenotypic changes in nitrate and nitrite reduction were tested. Our analyses demonstrated that the Lys-91 residue played a key role in nitrate reduction for quinol oxidation and the Asp-166 residue might influence the maturation of CymA. The Asp-97 residue might be one of the key factors that influence the interaction of CymA with the cytochromes NapB and NrfA.", }