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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
21
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pubmed:dateCreated |
1991-12-3
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pubmed:abstractText |
Sensory rhodopsin I (SR-I) and bacteriorhodopsin (BR) from Halobacterium halobium show broad structural and spectroscopic similarities and yet perform distinct functions: photosensory reception and proton pumping, respectively. Probing the photoactive sites of SR-I and BR with 24 retinal analogs reveals differences in the protein environments near the retinal 13-methyl group and near the beta-ionone ring. 13-cis-Retinal does not form a retinylidene pigment with the SR-I apoprotein, although this isomer binds to the BR apoprotein even more rapidly than all-trans-retinal, the functional isomer of both pigments. The activation of both SR-I and BR requires all-trans/13-cis isomerization of retinal;however, a steric interaction between the retinal 13-methyl group and the protein is required for SR-I activation but not for that of BR. These results reveal a key difference between SR-I and BR that is likely to be the initial diverging point in their photoactivation pathways. We propose the 13-methyl group-protein interaction functions as a trigger for SR-I activation--i.e., converts photon absorption by the chromophore into protein conformational changes. A similar steric trigger is essential for activation of mammalian rhodopsin, indicating a common mechanism for receptor activation in archaebacterial and vertebrate retinylidene photosensors.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-19246,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2252905,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2306497,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2344465,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2359127,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2505843,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2591367,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2808377,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2930820,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2937462,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-2988577,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-3159027,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-3293584,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-34224,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-3449857,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-3551758,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-4016190,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-4415495,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-6281770,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-6287921,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-6323178,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-6477881,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-6504161,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-7213600,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-7378129,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1946353-7387982
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0027-8424
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
88
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
9412-6
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:1946353-Apoproteins,
pubmed-meshheading:1946353-Bacteriorhodopsins,
pubmed-meshheading:1946353-Binding Sites,
pubmed-meshheading:1946353-Halobacterium,
pubmed-meshheading:1946353-Halorhodopsins,
pubmed-meshheading:1946353-Photochemistry,
pubmed-meshheading:1946353-Protein Conformation,
pubmed-meshheading:1946353-Retinaldehyde,
pubmed-meshheading:1946353-Sensory Rhodopsins,
pubmed-meshheading:1946353-Signal Transduction,
pubmed-meshheading:1946353-Spectrum Analysis,
pubmed-meshheading:1946353-Stereoisomerism,
pubmed-meshheading:1946353-Structure-Activity Relationship
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pubmed:year |
1991
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pubmed:articleTitle |
Mechanism of activation of sensory rhodopsin I: evidence for a steric trigger.
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pubmed:affiliation |
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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