Linked Life Data

11258895

Source:http://linkedlifedata.com/resource/pubmed/id/11258895

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2001-3-22
pubmed:abstractText
13C-NMR relaxation experiments (T(1), T(2), T(1)(rho), and NOE) were performed on selectively enriched residues in two peptides, one hydrophobic staple alpha-helix-forming peptide GFSKAELAKARAAKRGGY and one beta-hairpin-forming peptide RGITVNGKTYGR, in water and in water/trifluoroethanol (TFE). Exchange contributions, R(ex), to spin-spin relaxation rates for (13)C(alpha) and (13)C(beta) groups were derived and were ascribed to be mainly due to peptide folding-unfolding. To evaluate the exchange time, tau(ex), from R(ex), the chemical shift difference between folded and unfolded states, Deltadelta, and the populations of these states, p(i), were determined from the temperature dependence of (13)C chemical shifts. For both peptides, values for tau(ex) fell in the 1 micros to 10 micros range. Under conditions where the peptides are most folded (water/TFE, 5 degrees C), tau(ex) values for all residues in each respective peptide were essentially the same, supporting the presence of a global folding-unfolding exchange process. Rounded-up average tau(ex) values were 4 micros for the helix peptide and 9 micros for the hairpin peptide. This 2-3-fold difference in exchange times between helix and hairpin peptides is consistent with that observed for folding-unfolding of other small peptides.
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
6
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2844-53
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Conformational exchange on the microsecond time scale in alpha-helix and beta-hairpin peptides measured by 13C NMR transverse relaxation.
pubmed:affiliation
Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Health Science Center, 321 Church Street, Minneapolis, Minnesota 55455, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't