Document Detail


Positioning proton-donating residues to the Schiff-base accelerates the M-decay of pharaonis phoborhodopsin expressed in Escherichia coli.
MedLine Citation:
PMID:  10443011     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Phoborhodopsin (also called sensory rhodopsin II, sR-II) is a receptor for the negative phototaxis of Halobacterium salinarum (pR), and pharaonis phoborhodopsin (ppR) is the corresponding receptor of Natronobacterium pharaonis. pR and ppR are retinoid proteins and have a photocycle similar to that of bacteriorhodopsin (bR). A major difference between the photocycle of the ion pump bR and the sensor pR or ppR is found in their turnover rates which are much faster for bR. A reason for this difference might be found in the lack of a proton-donating residue to the Schiff base which is formed between the lysine of the opsin and retinal. To reconstruct a bR-like photochemical behavior, we expressed ppR mutants in Escherichia coli in which proton-donating groups have been reintroduced into the cytoplasmic proton channel. In measurement of the photocycle it could be shown that the F86D mutant of ppR (Phe86 was substituted by Asp) showed a faster decay of M-intermediate than the wild-type, which was even accelerated in the F86D/L40T double mutant.
Authors:
M Iwamoto; K Shimono; M Sumi; N Kamo
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biophysical chemistry     Volume:  79     ISSN:  0301-4622     ISO Abbreviation:  Biophys. Chem.     Publication Date:  1999 Jun 
Date Detail:
Created Date:  1999-09-07     Completed Date:  1999-09-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0403171     Medline TA:  Biophys Chem     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  187-92     Citation Subset:  IM    
Affiliation:
Laboratory of Biophysical Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
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MeSH Terms
Descriptor/Qualifier:
Archaeal Proteins*
Bacteriorhodopsins / chemistry*,  genetics,  metabolism*
Base Sequence
Carotenoids*
DNA Primers / genetics
Escherichia coli / genetics
Gene Expression
Halobacterium salinarum / metabolism
Halorhodopsins*
Kinetics
Natronobacterium / genetics,  metabolism
Photochemistry
Point Mutation
Protons
Schiff Bases / chemistry,  metabolism
Sensory Rhodopsins*
Chemical
Reg. No./Substance:
0/Archaeal Proteins; 0/DNA Primers; 0/Halorhodopsins; 0/Protons; 0/Schiff Bases; 0/Sensory Rhodopsins; 0/sensory rhodopsin II protein, archaeal; 36-88-4/Carotenoids; 53026-44-1/Bacteriorhodopsins

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