title: Photocycle of the LOV-STAS protein from the pathogen Listeria monocytogenes.
abstract: Listeria monocytogenes, a food-borne bacterial pathogen causing significant human mortality, propagates by expressing genes in response to environmental signals, such as temperature and pH. Listeria gene (lmo0799) encodes a protein homologous to the Bacillus subtilis YtvA, which has a flavin-light, oxygen or voltage (LOV) domain and a Sulfate Transporters Anti-Sigma factor antagonist (STAS) output domain that regulates transcription-initiation factor Sigma B in the bacterial stress response upon exposure to light. This could be significant for the pathogenesis of listeriosis because Sigma B has been linked to virulence of Listeria, and the Listeria Lmo0799 protein has recently been identified as a virulence factor activated by blue light. We have cloned, expressed heterologously in Escherichia coli and purified the full-length LM-LOV-STAS protein. Although it exhibits photochemical activity similar to that of YtvA, LM-LOV-STAS lacks an almost universally conserved arginine in the flavin-binding site, as well as another positively charged residue, a lysine in YtvA. The absence of these positive charges was found to destabilize retention of the flavin mononucleotide (FMN) chromophore in the LM-LOV-STAS protein, particularly at higher temperatures. The unusual sequence of the LM-LOV-STAS protein alters both spectral features and activation/deactivation kinetics, potentially expanding the sensory capacity of this LOV domain, e.g. to detect light plus cold.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.
authors.forename: Ruby H
authors.initials: RH
authors.lastname: Chan
authors.forename: James W
authors.initials: JW
authors.lastname: Lewis
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Bogomolni
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry / Q000235:genetics; D001412:Bacillus subtilis / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005486:Flavin Mononucleotide / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects*; D007700:Kinetics; D008027:Light; D008089:Listeria monocytogenes / Q000737:chemistry / Q000235:genetics / Q000528:radiation effects*; D008239:Lysine / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D037521:Virulence Factors / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D037521:Virulence Factors; D005486:Flavin Mononucleotide; D001120:Arginine; D008239:Lysine