title: The RavA-ViaA Chaperone-Like System Interacts with and Modulates the Activity of the Fumarate Reductase Respiratory Complex.
abstract: Regulatory ATPase variant A (RavA) is a MoxR AAA+ protein that functions together with a partner protein that we termed VWA interacting with AAA+ ATPase (ViaA) containing a von Willebrand Factor A domain. However, the functional role of RavA-ViaA in the cell is not yet well established. Here, we show that RavA-ViaA are functionally associated with anaerobic respiration in Escherichia coli through interactions with the fumarate reductase (Frd) electron transport complex. Expression analysis of ravA and viaA genes showed that both proteins are co-expressed with multiple anaerobic respiratory genes, many of which are regulated by the anaerobic transcriptional regulator Fnr. Consistently, the expression of both ravA and viaA was found to be dependent on Fnr in cells grown under oxygen-limiting condition. ViaA was found to physically interact with FrdA, the flavin-containing subunit of the Frd complex. Both RavA and the Fe-S-containing subunit of the Frd complex, FrdB, regulate this interaction. Importantly, Frd activity was observed to increase in the absence of RavA and ViaA. This indicates that RavA and ViaA modulate the activity of the Frd complex, signifying a potential regulatory chaperone-like function for RavA-ViaA during bacterial anaerobic respiration with fumarate as the terminal electron acceptor.
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario, M5G 1M1, Canada.
authors.forename: Keith S
authors.initials: KS
authors.lastname: Wong
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario, M5G 1M1, Canada.
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Bhandari
authors.affiliation: Department of Biohealth Informatics, School of Informatics and Computing, Indiana University Purdue University, Indianapolis, IN 46202, USA.
authors.forename: Sarath Chandra
authors.initials: SC
authors.lastname: Janga
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario, M5G 1M1, Canada; Department of Chemistry, University of Toronto, Toronto, Ontario, M5S 3H6, Canada. Electronic address: walid.houry@utoronto.ca.
authors.forename: Walid A
authors.initials: WA
authors.lastname: Houry
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004579:Electron Transport; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000235:genetics; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics; D013385:Succinate Dehydrogenase / Q000737:chemistry* / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; C060704:FNR protein, E coli; D007506:Iron-Sulfur Proteins; D018832:Molecular Chaperones; C033727:fumarate reductase complex; D013385:Succinate Dehydrogenase; D000251:Adenosine Triphosphatases; C508688:RavA protein, E coli
keywords: ATPases associated with diverse cellular activities (AAA); chaperone; flavoprotein; respiratory chain; von Willebrand factor A domain