title: A halorhodopsin-overproducing mutant isolated from an extremely haloalkaliphilic archaeon Natronomonas pharaonis.
abstract: The halorhodopsin (hR)-overproducing mutant strain KM-1 was isolated from the extremely haloalkaliphilic archaeon Natronomonas pharaonis type strain DSM2160(T). hR-enriched membranes were easily obtained by washing the cells with distilled water. The membranes were claret colored owing to two pigments: hR and bacterioruberin. The hR component in the absorption spectra changed from blue to purple upon the addition of Cl(-) and had a K(m) value of 1.7 mM. Overexpression of hR in strain KM-1 might be caused by the point mutation Asp324-->Asn in the bacteriorhodopsin activator homologues of N. pharaonis. The mutation changed the hR-expression pattern from inducible to constitutive in the late exponential phase.
authors.affiliation: Center for Gene Research, Nagoya University, Chikusa-ku Furo-cho 1, Nagoya, Japan. ihara@gene.nagoya-u.ac.jp
authors.forename: Kunio
authors.initials: K
authors.lastname: Ihara
authors.forename: Akihiro
authors.initials: A
authors.lastname: Narusawa
authors.forename: Keita
authors.initials: K
authors.lastname: Maruyama
authors.forename: Masashi
authors.initials: M
authors.lastname: Takeguchi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kouyama
mesh_terms: D019943:Amino Acid Substitution; D001216:Asparagine / Q000235:genetics / Q000378:metabolism; D001224:Aspartic Acid / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D006216:Halobacteriaceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D025602:Halorhodopsins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D009154:Mutation
chemical_list: D025602:Halorhodopsins; D001224:Aspartic Acid; D001216:Asparagine