Linked Life Data

7797251

Source:http://linkedlifedata.com/resource/pubmed/id/7797251

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1995-8-3
pubmed:abstractText
The human class I major histocompatibility complex (MHC) encoded molecule HLA-A2 loaded with the high-affinity peptide GILGRVFTL (p790), was studied by means of steady-state and picosecond fluorescence intensity and fluorescence anisotropy methods. The large number of tryptophan residues (W) (10 W/heavy chain, 2 W/beta 2m) as well as their fluorescence sensitivity to the microenvironment, determine the emission of the studied complex. The HLA-A2/peptide complex exhibits a considerable static inhomogeneous broadening (IB) of the W electronic spectra, which results in a dependence of the steady-state fluorescence spectrum on the excitation wavelength. The high concentration of W's chromophores and the spectral IB cause a directed non-radiative migration of electronic excitation energy by Foerster's mechanism from 'blue' W residues to 'red' ones. This phenomenon manifests itself in a nanosecond fluorescence spectral shift and an accelerated fluorescence depolarization at the red edge of the emission spectrum. Selective excitation at the red edge of the W absorption band (310 nm) provided a space selective reduction in the number of excited chromophores and enabled resolution of the emission of the 'red' subset of the protein's tryptophans. This avoided the non-radiative homo-energy transfer and enabled to study the fluorescence anisotropy decay kinetics of these residues without a distortion by the energy transfer (ET) process. Under these experimental conditions the fluorescence anisotropy decays practically from the limiting anisotropy value (0.3) for W in a bi-exponential process. The longer decay constant has a value larger than that expected for a global rotation of the HLA-A2/peptide complex suggesting that the protein molecules exist in an oligomeric form.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0165-2478
pubmed:author
pubmed:issnType
Print
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
195-201
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Selective steady-state and time-resolved fluorescence spectroscopy of an HLA-A2-peptide complex.
pubmed:affiliation
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't