Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-1-24
pubmed:abstractText
Femtosecond time-resolved transient absorption spectroscopy was employed to characterize for the first time the primary photoisomerization dynamics of a bacterial phytochrome system in the two thermally stable states of the photocycle. The 85-kDa phytochrome Cph1 from the cyanobacterium Synechocystis PCC 6803 expressed in Escherichia coli was reconstituted with phycocyanobilin (Cph1-PCB) and phycoerythrobilin (Cph1-PEB). The red-light-absorbing form Pr of Cph1-PCB shows an approximately 150 fs relaxation in the S(1) state after photoexcitation at 650 nm. The subsequent Z-E isomerization between rings C and D of the linear tetrapyrrole-chromophore is best described by a distribution of rate constants with the first moment at (16 ps)(-1). Excitation at 615 nm leads to a slightly broadened distribution. The reverse E-Z isomerization, starting from the far-red-absorbing form Pfr, is characterized by two shorter time constants of 0.54 and 3.2 ps. In the case of Cph1-PEB, double-bond isomerization does not take place, and the excited-state lifetime extends into the nanosecond regime. Besides a stimulated emission rise time between 40 and 150 fs, no fast relaxation processes are observed. This suggests that the chromophore-protein interaction along rings A, B, and C does not contribute much to the picosecond dynamics observed in Cph1-PCB but rather the region around ring D near the isomerizing C(15) [double bond] C(16) double bond. The primary reaction dynamics of Cph1-PCB at ambient temperature is found to exhibit very similar features as those described for plant type A phytochrome, i.e., a relatively slow Pr, and a fast Pfr, photoreaction. This suggests that the initial reactions were established already before evolution of plant phytochromes began.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-10466717, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-10818798, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-10913241, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-11141069, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-11277928, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-11532008, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-1191643, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-16593380, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-17783735, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-4012322, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-7654704, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-7732376, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-7794904, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-7939680, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-8338849, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-8718870, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-8765662, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-8901532, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-8973170, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9109482, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9278513, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9341232, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9342316, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9382811, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9487803, http://linkedlifedata.com/resource/pubmed/commentcorrection/11806940-9867036
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:volume
82
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1004-16
pubmed:dateRevised
2010-9-14
pubmed:meshHeading
pubmed-meshheading:11806940-Biophysical Phenomena, pubmed-meshheading:11806940-Biophysics, pubmed-meshheading:11806940-Carbon, pubmed-meshheading:11806940-Cyanobacteria, pubmed-meshheading:11806940-Cysteine, pubmed-meshheading:11806940-Escherichia coli, pubmed-meshheading:11806940-Kinetics, pubmed-meshheading:11806940-Light, pubmed-meshheading:11806940-Models, Chemical, pubmed-meshheading:11806940-Models, Statistical, pubmed-meshheading:11806940-Phycobilins, pubmed-meshheading:11806940-Phycocyanin, pubmed-meshheading:11806940-Phycoerythrin, pubmed-meshheading:11806940-Phytochrome, pubmed-meshheading:11806940-Plants, pubmed-meshheading:11806940-Protein Conformation, pubmed-meshheading:11806940-Pyrroles, pubmed-meshheading:11806940-Spectrophotometry, pubmed-meshheading:11806940-Tetrapyrroles, pubmed-meshheading:11806940-Time Factors
pubmed:year
2002
pubmed:articleTitle
Ultrafast dynamics of phytochrome from the cyanobacterium synechocystis, reconstituted with phycocyanobilin and phycoerythrobilin.
pubmed:affiliation
Institut für Experimentalphysik, Freie Universität Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't