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Titolo:
Disrupting helix formation in unsolvated peptides
Autore:
Kaleta, DT; Jarrold, MF;
Indirizzi:
Northwestern Univ, Dept Chem, Evanston, IL 60208 USA Northwestern Univ Evanston IL USA 60208 Dept Chem, Evanston, IL 60208 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 19, volume: 105, anno: 2001,
pagine: 4436 - 4440
SICI:
1520-6106(20010517)105:19<4436:DHFIUP>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATIONS; ALANINE-BASED PEPTIDES; ION MOBILITY MEASUREMENTS; SALT-BRIDGE STRUCTURES; GAS-PHASE; FORMING TENDENCIES; ALPHA-HELIX; AMINO-ACIDS; AB-INITIO; IN-VACUO;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Kaleta, DT Northwestern Univ, Dept Chem, 2145 Sheridan Rd, Evanston, IL 60208 USA Northwestern Univ 2145 Sheridan Rd Evanston IL USA 60208 08 USA
Citazione:
D.T. Kaleta e M.F. Jarrold, "Disrupting helix formation in unsolvated peptides", J PHYS CH B, 105(19), 2001, pp. 4436-4440

Abstract

Protonated polyalanine peptides form helices in the gas phase when their most basic protonation site (the N-terminus) is blocked by acetylation: Ac-A(a)+H+ (Ac acetyl and A = alanine). The glycine analogues, Ac-G(n)+H+ (G glycine), on the other hand, form random globules. The disruption of helix formation in unsolvated Ac-A(n)G(x)A(m)+H+ peptides has been examined as a function of n+m, and x using high resolution ion mobility measurements and molecular dynamics simulations. A surprisingly large block of glycine residues is required to disrupt helix formation in these peptides. For example, Ac-A(5)G(3)A(5)+H+ and AC-A(6)G(5)A(6)+H+ both remain helical at room temperature. According to molecular dynamics simulations, the glycines do not cause a localized disruption of the helices, as might be expected for a residueconsidered a helix breaker. This is consistent with helix disruption occurring through a global effect on the relative energies of the helix and globule rather than through a localized entropic effect.

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Documento generato il 30/03/20 alle ore 19:45:57