title: Formation of a distinctive complex between the inducible bacterial lysine decarboxylase and a novel AAA+ ATPase.
abstract: AAA+ ATPases are ubiquitous proteins that employ the energy obtained from ATP hydrolysis to remodel proteins, DNA, or RNA. The MoxR family of AAA+ proteins is widespread throughout bacteria and archaea but is largely uncharacterized. Limited work with specific members has suggested a potential role as molecular chaperones involved in the assembly of protein complexes. As part of an effort aimed at determining the function of novel AAA+ chaperones in Escherichia coli, we report the characterization of a representative member of the MoxR family, YieN, which we have renamed RavA (regulatory ATPase variant A). We show that the ravA gene exists on an operon with another gene encoding a protein, YieM, of unknown function containing a Von Willebrand Factor Type A domain. RavA expression is under the control of the sigmaS transcription factor, and its levels increase toward late log/early stationary phase, consistent with its possible role as a general stress-response protein. RavA functions as an ATPase and forms hexameric oligomers. Importantly, we demonstrate that RavA interacts strongly with inducible lysine decarboxylase (LdcI or CadA) forming a large cage-like structure consisting of two LdcI decamers linked by a maximum of five RavA oligomers. Surprisingly, the activity of LdcI does not appear to be affected by binding to RavA in a number of in vitro and in vivo assays, however, complex formation results in the stimulation of RavA ATPase activity. Data obtained suggest that the RavA-LdcI interaction may be important for the regulation of RavA activity against its targets.
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
authors.forename: Jamie
authors.initials: J
authors.lastname: Snider
authors.forename: Irina
authors.initials: I
authors.lastname: Gutsche
authors.forename: Michelle
authors.initials: M
authors.lastname: Lin
authors.forename: Sabulal
authors.initials: S
authors.lastname: Baby
authors.forename: Brian
authors.initials: B
authors.lastname: Cox
authors.forename: Gareth
authors.initials: G
authors.lastname: Butland
authors.forename: Jack
authors.initials: J
authors.lastname: Greenblatt
authors.forename: Andrew
authors.initials: A
authors.lastname: Emili
authors.forename: Walid A
authors.initials: WA
authors.lastname: Houry
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D002262:Carboxy-Lyases / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D017124:Conserved Sequence; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D029968:Escherichia coli Proteins; D000251:Adenosine Triphosphatases; C508688:RavA protein, E coli; D002262:Carboxy-Lyases; C021520:lysine decarboxylase