Linked Life Data

19422251

Source:http://linkedlifedata.com/resource/pubmed/id/19422251

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2009-5-28
pubmed:abstractText
Bacteriorhodopsin, reconstituted with a sterically "locked" retinal chromophore, BR5.12, has frequently been used to elucidate elementary photoinduced processes in the native pigment bacteriorhodopsin. In this work, the vibrational response of BR5.12 to photoexcitation is investigated by means of femtosecond time-resolved mid-infrared and UV-vis spectroscopy. The electronically excited state of BR5.12 decays with a time constant of 18 ps. Neither in the UV-vis nor in the mid-IR spectral region are indications found for chromophore photoproducts, besides the full recovery of the electronic ground state. However, vibrational bands are observed at around 1660 and 1550 cm(-1) in the protein amide I and amide II band regions, respectively. They are formed within a few picoseconds or even instantaneously. Thus, they appear faster than the S1 decay and persist for at least 130 ps, i.e., for much longer than the S1 lifetime. These findings strongly suggest that the observed bands must be assigned to protein vibrations and that they are not caused by a photoinduced temperature rise. Thus, for the first time, ultrafast protein vibrational changes are detected in BR5.12, that are not associated with isomerization. Possibly they can be related to the enhanced chemical reactivity of photoactivated BR5.12 reported in the literature. In wild-type bacteriorhodopsin, bands with very similar spectral and kinetic characteristics are observed, suggesting that they might originate from a similar mechanism which is not isomerization. A plausible mechanism is a polarization induced protein conformational change, as discussed in the literature.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1520-6106
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
113
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7851-60
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Ultrafast protein conformational alterations in bacteriorhodopsin and its locked analogue BR5.12.
pubmed:affiliation
Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't