Peptide Folding Dynamics: A Time-Resolved Study from the Nanosecond to the Microsecond Time Regime
详细信息 查看全文
- 作者：Mariano Venanzi ; Emanuela Gatto ; Gianfranco Bocchinfuso ; Antonio Palleschi ; Lorenzo Stella ; Chiara Baldini ; Fernando Formaggio ; Claudio Toniolo
- 刊名：Journal of Physical Chemistry B
- 出版年：2006
- 出版时间：November 16, 2006
- 年：2006
- 卷：110
- 期：45
- 页码：22834 - 22841
- 全文大小：216K
- 年卷期：v.110,no.45(November 16, 2006)
- ISSN：1520-5207
文摘
Time-resolved spectroscopies, spanning from the nanosecond to the microsecond time regime, coupled withmolecular mechanics calculations, allowed us to assess the most populated conformations in solution of aseries of analogues of trichogin GA IV, a natural undecapeptide showing significant antimicrobial activity.This peptide is characterized by a high content of the conformationally constrained 
-aminoisobutyric acidand by a glycine-glycine motif in the central part of the sequence. Nanosecond time-resolved fluorescenceexperiments were performed to determine the conformational properties of the peptide analogues in solution,while transient absorption measurements allowed us to study the peptide dynamics on the microsecond timescale. Because the peptides examined were functionalized by a fluorescent probe at the N-terminus and anitroxide quencher placed along the backbone at three different positions, the distance-dependent fluorophore-quencher interaction was exploited to obtain a deeper insight into their three-dimensional structural anddynamical properties. Further information on the conformational and dynamical features was obtained byphotophysical experiments as a function of the viscosity and polarity of the medium. Taken together, theresults revealed a transition from an elongated, helical conformation to a family of compact, folded structuresmimicking a helix-turn-helix motif, which may represent a model of the early steps of the protein hydrophobiccollapse.
-aminoisobutyric acidand by a glycine-glycine motif in the central part of the sequence. Nanosecond time-resolved fluorescenceexperiments were performed to determine the conformational properties of the peptide analogues in solution,while transient absorption measurements allowed us to study the peptide dynamics on the microsecond timescale. Because the peptides examined were functionalized by a fluorescent probe at the N-terminus and anitroxide quencher placed along the backbone at three different positions, the distance-dependent fluorophore-quencher interaction was exploited to obtain a deeper insight into their three-dimensional structural anddynamical properties. Further information on the conformational and dynamical features was obtained byphotophysical experiments as a function of the viscosity and polarity of the medium. Taken together, theresults revealed a transition from an elongated, helical conformation to a family of compact, folded structuresmimicking a helix-turn-helix motif, which may represent a model of the early steps of the protein hydrophobiccollapse.