Linked Life Data

8443171

Source:http://linkedlifedata.com/resource/pubmed/id/8443171

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1993-4-8
pubmed:abstractText
Fourier transform infrared difference spectroscopy has been used to study the photocycle of the mutant Tyr-185-->Phe expressed in native Halobacterium halobium and isolated as intact purple membrane fragments. We find several changes in the low-temperature bR-->K, bR-->L, and bR-->M FTIR difference spectra of Y185F relative to wild-type bR which are not directly related to the absorption bands associated with Tyr-185. We show that these features arise from the photoreaction of a stable red-shifted species (OY185F) with a vibrational spectrum similar to the O intermediate. By using photoselection and FTIR spectroscopy, we have been able to characterize the photoproducts of this OY185F species. A K-like photoproduct is formed at 80 K which has a 13-cis structure. However, it differs from K630, exhibiting an intense band at 990 cm-1 most likely due to a hydrogen-out-of-plane vibrational mode of the chromophore. At 170 and 250 K, photoexcitation of OY185F produces an intermediate with vibrational features similar to the N intermediate in the wild-type bR photocycle. However, no evidence for an M-like intermediate is found. Although Asp-96 undergoes a change in its environment/protonation state during the OY185F photocycle, no protonation changes involving Asp-85 and Asp-212 were detected. These results provide strong evidence that light adaptation of Y185F produces two species similar to bR570 and the O intermediate. Differences in their respective photocycles can be explained on the basis of differences in the protonation states of the residues Asp-85 and Asp-212 which are ionized in bR570 and undergo net protonation upon OY185F formation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2282-90
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
FTIR difference spectroscopy of the bacteriorhodopsin mutant Tyr-185-->Phe: detection of a stable O-like species and characterization of its photocycle at low temperature.
pubmed:affiliation
Physics Department, Boston University, Massachusetts 02215.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.