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Titolo:
Observation of the closing of individual hydrogen bonds during TFE-inducedhelix formation in a peptide
Autore:
Jaravine, VA; Alexandrescu, AT; Grzesiek, S;
Indirizzi:
Univ Basel, Biozentrum, Dept Biol Struct, CH-4056 Basel, Switzerland Univ Basel Basel Switzerland CH-4056 Struct, CH-4056 Basel, Switzerland Univ Connecticut, Dept Mol & Cell Biol, Storrs, CT 06269 USA Univ Connecticut Storrs CT USA 06269 ol & Cell Biol, Storrs, CT 06269 USA
Titolo Testata:
PROTEIN SCIENCE
fascicolo: 5, volume: 10, anno: 2001,
pagine: 943 - 950
SICI:
0961-8368(200105)10:5<943:OOTCOI>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR-MAGNETIC-RESONANCE; ALANINE-BASED PEPTIDES; RIBONUCLEASE-A; S-PEPTIDE; SCALAR COUPLINGS; ALPHA-HELIX; NMR EVIDENCE; STOP SIGNAL; PROTEIN; TRIFLUOROETHANOL;
Keywords:
S-peptide; RnaseA; J-coupling; NMR; scalar coupling; protein folding;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Grzesiek, S Univ Basel, Biozentrum, Dept Biol Struct, Klingelberstr 70, CH-4056 Basel,Switzerland Univ Basel Klingelberstr 70 Basel Switzerland CH-4056 zerland
Citazione:
V.A. Jaravine et al., "Observation of the closing of individual hydrogen bonds during TFE-inducedhelix formation in a peptide", PROTEIN SCI, 10(5), 2001, pp. 943-950

Abstract

Helix formation of an S-peptide analog, comprising the first 20 residues of Ribonuclease A and two additional N-terminal residues, was studied by measuring hydrogen bond (H-bond) (h3)J(NC') scalar couplings as a function of 2,2,2-trifluoroethanol (TFE) concentration. The (h3)J(NC') couplings give direct evidence for the closing of individual backbone N-H . .O=C H-bonds during the TFE-induced formation of secondary structure. Whereas no (h3)J(NC') correlations could be detected without TFE, alpha -helical (i,i +4) H-bond correlations were observed for the amides of residues A5 to M15 in the presence of TFE. The analysis of individual coupling constants indicates thata-helix formation starts at the center of the S-peptide around residue Elland proceeds gradually from there to both peptide ends as the TFE concentration is increased. At 60% to 90% TFE, well-formed a-helical H-bonds were observed for the amides hydrogens of residues K9 to Q13, whereas H-bonds of residues T5 to A8, H14, and M15 are affected by fraying. No intramolecular backbone H-bonds are present at and beyond the putative helix stop signal D16. As the (h3)J(NC') constants represent ensemble averages and the dependence of (h3)J(NC') on H-bond lengths is very steep, the size of the individual (h3)J(NC') coupling constants can be used as a measure for the population of a closed H-bond. These individual populations sire in agreement with results derived from the Lifson-Roig theory for coil-to-helix transitions. The present work shows that the closing of individual H-bonds during TFE-induced helix formation can be monitored by changes in the size of H-bond scalar couplings.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/07/20 alle ore 07:09:02