title: Identification of the YfgF MASE1 domain as a modulator of bacterial responses to aspartate.
abstract: Complex 3'-5'-cyclic diguanylic acid (c-di-GMP) responsive regulatory networks that are modulated by the action of multiple diguanylate cyclases (DGC; GGDEF domain proteins) and phosphodiesterases (PDE; EAL domain proteins) have evolved in many bacteria. YfgF proteins possess a membrane-anchoring domain (MASE1), a catalytically inactive GGDEF domain and a catalytically active EAL domain. Here, sustained expression of the Salmonella enterica spp. Enterica ser. Enteritidis YfgF protein is shown to mediate inhibition of the formation of the aspartate chemotactic ring on motility agar under aerobic conditions. This phenomenon was c-di-GMP-independent because it occurred in a Salmonella strain that lacked the ability to synthesize c-di-GMP and also when PDE activity was abolished by site-directed mutagenesis of the EAL domain. YfgF-mediated inhibition of aspartate chemotactic ring formation was impaired in the altered redox environment generated by exogenous p-benzoquinone. This ability of YfgF to inhibit the response to aspartate required a motif, (213)Lys-Lys-Glu(215), in the predicted cytoplasmic loop between trans-membrane regions 5 and 6 of the MASE1 domain. Thus, for the first time the function of a MASE1 domain as a redox-responsive regulator of bacterial responses to aspartate has been shown.
authors.affiliation: Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK. m.lacey@shu.ac.uk
authors.forename: Melissa
authors.initials: M
authors.lastname: Lacey
authors.forename: Agnieshka
authors.initials: A
authors.lastname: Agasing
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lowry
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Green
mesh_terms: D020816:Amino Acid Motifs; D001224:Aspartic Acid / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016227:Benzoquinones / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D019779:Salmonella enterica / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D016227:Benzoquinones; D001224:Aspartic Acid; C004532:quinone; C062025:bis(3',5')-cyclic diguanylic acid; D010727:Phosphoric Diester Hydrolases; D006152:Cyclic GMP
keywords: MASE1 domain; Salmonella; chemotaxis; cyclic-di-GMP; oxidative stress