title: Importance of the broad regional interaction for spectral tuning in Natronobacterium pharaonis phoborhodopsin (sensory rhodopsin II).
abstract: Natronobacterium pharaonis phoborhodopsin (ppR; also called N. pharaonis sensory rhodopsin II, NpsRII) is a photophobic sensor in N. pharaonis, and has a shorter absorption maximum (lambdamax, 500 nm) than those of other archaeal retinal proteins (lambdamax, 560-590 nm) such as bacteriorhodopsin (bR). We constructed chimeric proteins between bR and ppR to investigate the long range interactions effecting the color regulation among archaeal retinal proteins. The lambdamax of B-DEFG/P-ABC was 545 nm, similar to that of bR expressed in Escherichia coli (lambdamax, 550 nm). B-DEFG/P-ABC means a chimera composed of helices D, E, F, and G of bR and helices A, B, and C of ppR. This indicates that the major factor(s) determining the difference in lambdamax between bR and ppR exist in helices DEFG. To specify the more minute regions for the color determination between bR and ppR, we constructed 15 chimeric proteins containing helices D, E, F, and G of bR. According to the absorption spectra of the various chimeric proteins, the interaction between helices D and E as well as the effect of the hydroxyl group around protonated Schiff base on helix G (Thr-204 for ppR and Ala-215 for bR) are the main factors for spectral tuning between bR and ppR.
authors.affiliation: Laboratory of Biophysical Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan. kaz@pharm.hokudai.ac.jp
authors.forename: Kazumi
authors.initials: K
authors.lastname: Shimono
authors.forename: Takanori
authors.initials: T
authors.lastname: Hayashi
authors.forename: Yukako
authors.initials: Y
authors.lastname: Ikeura
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sudo
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Kamo
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry*; D001436:Bacteriorhodopsins / Q000737:chemistry; D002338:Carotenoids / Q000737:chemistry*; D003116:Color; D025602:Halorhodopsins; D008081:Liposomes; D008969:Molecular Sequence Data; D019633:Natronobacterium / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D025603:Sensory Rhodopsins; D013057:Spectrum Analysis
chemical_list: D019843:Archaeal Proteins; D025602:Halorhodopsins; D008081:Liposomes; D011993:Recombinant Fusion Proteins; D025603:Sensory Rhodopsins; C061508:sensory rhodopsin II protein, archaeal; D002338:Carotenoids; D001436:Bacteriorhodopsins