Publication Date:
2001-07-14
Description:
We report an atomic-resolution structure for a sensory member of the microbial rhodopsin family, the phototaxis receptor sensory rhodopsin II (NpSRII), which mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The 2.4 angstrom structure reveals features responsible for the 70- to 80-nanometer blue shift of its absorption maximum relative to those of haloarchaeal transport rhodopsins, as well as structural differences due to its sensory, as opposed to transport, function. Multiple factors appear to account for the spectral tuning difference with respect to bacteriorhodopsin: (i) repositioning of the guanidinium group of arginine 72, a residue that interacts with the counterion to the retinylidene protonated Schiff base; (ii) rearrangement of the protein near the retinal ring; and (iii) changes in tilt and slant of the retinal polyene chain. Inspection of the surface topography reveals an exposed polar residue, tyrosine 199, not present in bacteriorhodopsin, in the middle of the membrane bilayer. We propose that this residue interacts with the adjacent helices of the cognate NpSRII transducer NpHtrII.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Luecke, H -- Schobert, B -- Lanyi, J K -- Spudich, E N -- Spudich, J L -- R01-GM27750/GM/NIGMS NIH HHS/ -- R01-GM29498/GM/NIGMS NIH HHS/ -- R01-GM59970/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2001 Aug 24;293(5534):1499-503. Epub 2001 Jul 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA. hudel@uci.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11452084" target="_blank"〉PubMed〈/a〉
Keywords:
Archaeal Proteins/chemistry/metabolism
;
Arginine/chemistry
;
Bacteriorhodopsins/*chemistry/metabolism
;
Binding Sites
;
*Carotenoids
;
Color
;
Crystallography, X-Ray
;
Electron Spin Resonance Spectroscopy
;
Hydrogen Bonding
;
Ion Transport
;
Light
;
Models, Molecular
;
Natronobacterium/*chemistry/metabolism
;
Protein Conformation
;
Protein Structure, Secondary
;
Protons
;
Retinaldehyde/chemistry/metabolism
;
Schiff Bases
;
Signal Transduction
;
Tyrosine/chemistry
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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