Vibrio cholerae FeoB contains a dual nucleotide-specific NTPase domain essential for ferrous iron uptake

• Published in: Proceedings of the National Academy of Sciences - PNAS 2019-03, Vol.116 (10), p.4599-4604
• Main Authors: Shin, Minhye, Mey, Alexandra R., Payne, Shelley M.
• Format: Article
• Language: English
• Subjects: Adenosine triphosphatase; Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; Amino Acid Motifs; Archaea; Asparagine; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological Sciences; Biological Transport; E coli; Ferrous Compounds - metabolism; Gene Expression Regulation, Bacterial; GTP Phosphohydrolases - chemistry; GTP Phosphohydrolases - genetics; GTP Phosphohydrolases - metabolism; Guanosine triphosphatases; Helicobacter pylori; Hydrogen bonding; Ion Transport; Iron; Membrane proteins; Mutants; Mutation; Nucleotides - metabolism; Pathogens; Protein Domains; Proteins; Residues; Serine; Transport; Vibrio cholerae; Vibrio cholerae - chemistry; Vibrio cholerae - enzymology; Vibrio cholerae - genetics; Vibrio cholerae - metabolism; Waterborne diseases
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1817964116

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.