Document Detail

Isolation and properties of the native chromoprotein halorhodopsin.
MedLine Citation:
PMID:  10872334     Owner:  NLM     Status:  MEDLINE    
The native chromoprotein of the light-driven chloride pump halorhodopsin (HR) was isolated from Halobacterium halobium strain L-33 which lacks bacteriorhodopsin but contains 'slow cycling rhodopsin-like pigment' (SR). A membrane fraction was prepared in low salt and dissolved in a high salt medium by the detergents Lubrol PX or octylglucoside. These conditions destroyed the chromophore of SR but not the HR pigment. Chromatography on phenyl-Sepharose and hydroxylapatite produced, in 60% yield, a 230-fold enriched monomeric chromoprotein with an apparent mol. wt. of 20,000. The chromoprotein was stable in 1 M NaCl and 1% octylglucoside and remained stable upon removal of detergent. It reacted with borohydride in the dark and with hydroxylamine in the light. The absorption maximum of the light-adapted state is at 580 + 2 nm and its molar extinction approximately 50,000/M/cm. Upon illumination in the presence of detergent it was converted into a 410 nm absorbing species with concomitant release of protons. A thermal reconversion to the 580 nm species occurred with a half time of 76 s at -6 degrees C. Blue light absorbed by the photoproduct accelerated the re-conversion as well as the re-uptake of protons. Removal of the detergent prevented the light-induced formation of the 410 nm species. Under these conditions a photochemical behaviour similar to that in intact cells and cell vesicles, i.e., a photocycle in the 10-20 ms range was observed. These findings form the basis for functional reconstitution of HR.
M Steiner; D Oesterhelt
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The EMBO journal     Volume:  2     ISSN:  0261-4189     ISO Abbreviation:  EMBO J.     Publication Date:  1983  
Date Detail:
Created Date:  2000-07-24     Completed Date:  2000-07-24     Revised Date:  2010-09-14    
Medline Journal Info:
Nlm Unique ID:  8208664     Medline TA:  EMBO J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1379-85     Citation Subset:  IM    
Max-Planck-Institut für Biochemie, Martinsried, FRG.
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MeSH Terms
Bacteriorhodopsins / analysis*
Halobacterium salinarum / chemistry*
Reg. No./Substance:
0/Halorhodopsins; 53026-44-1/Bacteriorhodopsins

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