title: Identification of a Vibrio cholerae chemoreceptor that senses taurine and amino acids as attractants.
abstract: Vibrio cholerae, the etiological agent of cholera, was found to be attracted by taurine (2-aminoethanesulfonic acid), a major constituent of human bile. Mlp37, the closest homolog of the previously identified amino acid chemoreceptor Mlp24, was found to mediate taxis to taurine as well as L-serine, L-alanine, L-arginine, and other amino acids. Methylation of Mlp37 was enhanced upon the addition of taurine and amino acids. Isothermal titration calorimetry demonstrated that a purified periplasmic fragment of Mlp37 binds directly to taurine, L-serine, L-alanine and L-arginine. Crystal structures of the periplamic domain of Mlp37 revealed that L-serine and taurine bind to the membrane-distal PAS domain in essentially in the same way. The structural information was supported by characterising the in vivo properties of alanine-substituted mutant forms of Mlp37. The fact that the ligand-binding domain of the L-serine complex had a small opening, which would accommodate a larger R group, accounts for the broad ligand specificity of Mlp37 and allowed us to visualise ligand binding to Mlp37 with fluorescently labelled L-serine. Taken together, we conclude that Mlp37 serves as the major chemoreceptor for taurine and various amino acids.
authors.affiliation: Department of Frontier Bioscience, Hosei University, Kajino-cho, Koganei, Tokyo 184-8584, Japan.|Research Center for Micro-Nano Technology, Hosei University, Midori-cho, Koganei, Tokyo, Japan.
authors.forename: So-ichiro
authors.initials: S
authors.lastname: Nishiyama
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka City 560-0043, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Frontier Bioscience, Hosei University, Kajino-cho, Koganei, Tokyo 184-8584, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Suzuki
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Itoh
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka City 560-0043, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Sumita
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka City 560-0043, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Uchida
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Homma
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka City 560-0043, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imada
authors.affiliation: Department of Frontier Bioscience, Hosei University, Kajino-cho, Koganei, Tokyo 184-8584, Japan.|Research Center for Micro-Nano Technology, Hosei University, Midori-cho, Koganei, Tokyo, Japan.
authors.forename: Ikuro
authors.initials: I
authors.lastname: Kawagishi
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001646:Bile / Q000737:chemistry; D002630:Chemotactic Factors; D002633:Chemotaxis; D008024:Ligands; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D017459:Receptors, Amino Acid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017981:Receptors, Neurotransmitter / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013654:Taurine / Q000737:chemistry; D014734:Vibrio cholerae / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002630:Chemotactic Factors; D008024:Ligands; D017459:Receptors, Amino Acid; D017981:Receptors, Neurotransmitter; C030803:taurine receptor; D013654:Taurine