Spectroscopic probes sensitive to intra-chain contact formation events in polypeptides are increasingly used to study the structural and dynamical properties of different amino acid sequences. Quenching of the triplet state of tryptophan by close contact with cysteine enables the measure of contact formation rates without the need of extrinsic probes, thus being suitable for the study of natural proteins and peptides. We illustrate the use of this method to investigate the conformational dynamics of beta-hairpin peptides and small two-state proteins in conditions close to native. The coexistence of folded and unfolded states can be revealed from the non-exponential relaxation of the excited triplet, enabling the characterization of both unfolded chain dynamics and folding kinetics. The contact formation rates measured in the disordered state are compared to those observed for model peptides. Using this approach we outline the kinetic pathway leading to the formation of the beta-hairpin structure of the C-terminal fragment of protein GB1, revealing the presence of misfolded states, as proposed in recent computational works.

Conformational dynamics of peptides and small proteins revealed by tryptophan-cysteine contact formation kinetics / M. Buscaglia, A. Soranno, R. Longhi, T. Bellini. ((Intervento presentato al 20. convegno SIBPA 2010 tenutosi a Arcidosso nel 2010.

Conformational dynamics of peptides and small proteins revealed by tryptophan-cysteine contact formation kinetics

M. Buscaglia
Primo
;
A. Soranno
Secondo
;
T. Bellini
Ultimo
2010

Abstract

Spectroscopic probes sensitive to intra-chain contact formation events in polypeptides are increasingly used to study the structural and dynamical properties of different amino acid sequences. Quenching of the triplet state of tryptophan by close contact with cysteine enables the measure of contact formation rates without the need of extrinsic probes, thus being suitable for the study of natural proteins and peptides. We illustrate the use of this method to investigate the conformational dynamics of beta-hairpin peptides and small two-state proteins in conditions close to native. The coexistence of folded and unfolded states can be revealed from the non-exponential relaxation of the excited triplet, enabling the characterization of both unfolded chain dynamics and folding kinetics. The contact formation rates measured in the disordered state are compared to those observed for model peptides. Using this approach we outline the kinetic pathway leading to the formation of the beta-hairpin structure of the C-terminal fragment of protein GB1, revealing the presence of misfolded states, as proposed in recent computational works.
12-set-2010
protein folding ; contact formation ; villin ; GB1 ; beta-hairpin ; tryptophan ; triplet state
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Conformational dynamics of peptides and small proteins revealed by tryptophan-cysteine contact formation kinetics / M. Buscaglia, A. Soranno, R. Longhi, T. Bellini. ((Intervento presentato al 20. convegno SIBPA 2010 tenutosi a Arcidosso nel 2010.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/164417
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