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Kinetics of the self-aggregation and film formation of poly-L-proline at high temperatures explored by circular dichroism spectroscopy.
Tooke, Lonna; Duitch, Laura; Measey, Thomas J; Schweitzer-Stenner, Reinhard.
Afiliación
  • Tooke L; Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
Biopolymers ; 93(5): 451-7, 2010 May.
Article en En | MEDLINE | ID: mdl-19998404
Poly-L-proline has been used as a model system for various purposes over a period of more than 60 years. Its relevance among the protein/peptide community stems from its use as a reference system for determining the conformational distributions of unfolded peptides and proteins, its use as a molecular ruler, and from the pivotal role of proline residues in conformational transitions and protein-protein interactions. While several studies indicate that polyproline can aggregate and precipitate in aqueous solution, a systematic study of the aggregation process is still outstanding. We found, by means of UV-circular dichroism and IR measurements, that polyproline is predominantly monomeric at room temperature at millimolar concentrations. Upon heating, the polypeptide stays in its monomeric state until the temperature reaches a threshold of ca. 60 degrees C. At higher temperatures, the peptide aggregates as a film on the inside surface of the employed cuvette. The process proceeds on a time scale of 10(3) s and can best be described by a bi-exponential relaxation function. The respective CD and IR spectra are qualitatively different from the canonical spectra of polyproline in aqueous solution, and are indicative of a highly packed state.
Asunto(s)

Texto completo: 1 Base de datos: MEDLINE Asunto principal: Péptidos / Dicroismo Circular / Calor Tipo de estudio: Prognostic_studies Idioma: En Revista: Biopolymers Año: 2010 Tipo del documento: Article

Texto completo: 1 Base de datos: MEDLINE Asunto principal: Péptidos / Dicroismo Circular / Calor Tipo de estudio: Prognostic_studies Idioma: En Revista: Biopolymers Año: 2010 Tipo del documento: Article