Linked Life Data

15170484

Source:http://linkedlifedata.com/resource/pubmed/id/15170484

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-6-1
pubmed:abstractText
Microbial rhodopsins undergo cyclic photochemical reactions (photocycles) in which proton transfers and conformational changes result in charge displacements during transitions between photocycle intermediates. We report a new photoelectric method to monitor charge movements during rhodopsin photocycling with fast kinetic resolution in suspensions of intact E. coli cells. The method monitors electrical currents resulting from asymmetric photoexcitation of microbial rhodopsins by a unilateral laser flash, and kinetically resolves intramolecular charge movements. We investigated E. coli-expressed proton-transporting rhodopsins, specifically green- and blue-absorbing proteorhodopsins (GPR and BPR, respectively) from uncultivated marine plankton, and sensory rhodopsins, namely receptors from Natronomonas pharaonis and Anabaena (Nostoc) sp. PCC7120. Kinetic components of the currents correlate with photochemical transformations of the pigments, and the integrated current measures net transport by the proton-pumping rhodopsins. The photoelectric measurements distinguish between known light-driven transporters and photosensors, and reveal differences in proton transfer reactions in the two tested proton pumps. Screening of nine newly identified proteorhodopsins reveals two with GPR-type charge movements, five with BPR-type, and two with the characteristics of the sensory rhodopsins. The approach developed in the present work provides a direct, rapid and informative method for studying electrogenic events in rhodopsin photocycles and also gives a clue to functions of newly found microbial rhodopsins in nature.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1474-905X
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
548-54
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Light-induced intramolecular charge movements in microbial rhodopsins in intact E. coli cells.
pubmed:affiliation
Center for Membrane Biology, Department of Biochemistry and Molecular Biology and Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX 77030, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural