title: Directed evolution of Vibrio fischeri LuxR signal sensitivity.
abstract: LuxR is the core component of Vibrio fischeri quorum sensing. It acts as the transcriptional activator by binding to its cognate signaling molecules 3-oxo-hexanoyl-homoserine lactone (3OC6HSL). Although several acyl-HSLs with 3-oxo groups are known to activate LuxR with similar efficiency, acyl-HSLs without 3-oxo groups are very weak inducers. We conducted a round of LuxR directed evolution to acquire LuxR mutants with higher signal sensitivity to octanoyl-homoserine lactone (C8HSL). All of the isolated mutants showed increased signal sensitivity to many other acyl-HSLs, including C8HSL, and some to the LuxR antagonist p-coumaroyl-HSL. The evolution of their ligand sensitivity proceeded through the stabilization of the signal-bound state, thereby elevating the effective concentration of LuxR at the ON-state.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tashiro
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan.
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan.
authors.forename: Shigeko
authors.initials: S
authors.lastname: Kawai-Noma
authors.affiliation: Department of Applied Chemistry and Biotechnology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba City, Chiba 263-8522, Japan. Electronic address: umeno@faculty.chiba-u.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Umeno
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D048908:Aliivibrio fischeri / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D019020:Directed Molecular Evolution / Q000379:methods*; D015964:Gene Expression Regulation, Bacterial; D016297:Mutagenesis, Site-Directed; D053038:Quorum Sensing / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins; C088386:homoserine lactone; D015107:4-Butyrolactone
keywords: Antagonist; Chemical chaperone; Genetic switch; Positive selection; Quorum sensing; Synthetic biology