期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：10
页码：4599-4604
DOI：10.1073/pnas.1817964116
出版社：The National Academy of Sciences of the United States of America
摘要：The Feo ferrous iron transporter is widely distributed among bacteria and archaea, but its mechanism of transport has not been fully elucidated. In Vibrio cholerae , the transport system requires three proteins: the small cytosolic proteins FeoA and FeoC and a large cytoplasmic-membrane–associated protein FeoB, which has an N-terminal G-protein domain. We show that, in contrast to Escherichia coli FeoB, which is solely a GTPase, the V. cholerae and Helicobacter pylori FeoB proteins have both GTPase and ATPase activity. In V. cholerae , mutation of the G4 motif, responsible for hydrogen bonding with the guanine base, abolished the GTPase activity but not ATPase activity. The ATPase activity of the G4 motif mutants was sufficient for Feo function in the absence of GTPase. We show that the serine and asparagine residues in the G5 motif likely play a role in the ATPase activity, and substitution of these residues with those found in the corresponding positions in E. coli FeoB resulted in similar nucleotide hydrolysis activity in the E. coli protein. These results add significantly to our understanding of the NTPase domain of FeoB and its role in Feo function.
关键词：Feo ; iron transport ; Vibrio cholerae ; GTPase ; ATPase
