title: Expression of salinarum halorhodopsin in Escherichia coli cells: solubilization in the presence of retinal yields the natural state.
abstract: Salinarum halorhodopsin (HsHR), a light-driven chloride ion pump of haloarchaeon Halobacterium salinarum, was heterologously expressed in Escherichia coli. The expressed HsHR had no color in the E. coli membrane, but turned purple after solubilization in the presence of all-trans retinal. This colored HsHR was purified by Ni-chelate chromatography in a yield of 3-4 mg per liter culture. The purified HsHR showed a distinct chloride pumping activity by incorporation into the liposomes, and showed even in the detergent-solubilized state, its typical behaviors in both the unphotolyzed and photolyzed states. Upon solubilization, HsHR expressed in the E. coli membrane attains the proper folding and a trimeric assembly comparable to those in the native membranes.
authors.affiliation: Faculty of Advanced Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Takashi
authors.initials: T
authors.lastname: Kikukawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Kamiya
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Aizawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kawano
authors.forename: Seiji
authors.initials: S
authors.lastname: Miyauchi
authors.forename: Naoki
authors.initials: N
authors.lastname: Kamo
authors.forename: Makoto
authors.initials: M
authors.lastname: Demura
mesh_terms: D001483:Base Sequence; D002850:Chromatography, Gel; D002942:Circular Dichroism; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D025602:Halorhodopsins / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012172:Retinaldehyde / Q000737:chemistry*; D012995:Solubility
chemical_list: D017931:DNA Primers; D025602:Halorhodopsins; D012172:Retinaldehyde