Effect of secondary structure on the interactions of peptide T4 LYS (11-36) in mixtures of aqueous sodium chloride and 2,2,2,-Trifluoroethanol

Anderson, Camille O. ; Spiegelberg, Susanne ; Prausnitz, John M. ; Blanch, Harvey W.

Lawrence Berkeley National Laboratory

关键词: Dimerization;    Lysozyme;    Diseases;    Mixtures;    Fluorescence;   

DOI  :  10.2172/837230
RP-ID  :  LBNL-49227
RP-ID  :  AC03-76SF00098
RP-ID  :  837230

美国|英语

来源: UNT Digital Library

【 摘 要 】

The potential of mean force for protein-protein interactions is key to the development of a statistical-mechanical model for salt-induced protein precipitation and crystallization, and for understanding certain disease states, including cataract formation and {beta}-amyloid pathology in Alzheimer's disease. Fluorescence anisotropy provides a method for quantitative characterization of intermolecular interactions due to reversible association. Monomer-dimer equilibria for the peptide T4 LYS(11-36) were studied by fluorescence anisotropy. This peptide, derived from the {beta}-sheet region of the T4 lysozyme molecule, has the potential to form amyloid fibrils. 2,2,2-trifluoroethanol (TFE) induces a change in peptide secondary structure, and was used in aqueous solutions at concentrations from 0 to 50% (v/v) at 25 and 37 C to examine the role of peptide conformation on peptide-peptide interactions. The association constant for dimerization increased with rising TFE concentration and with falling temperature. The peptide-peptide potential of mean force was computed from these association constants. Circular-dichroism measurements showed that the secondary structure of the peptide plays an important role in these strong attractive interactions due to intermolecular hydrogen-bond formation and hydrophobic interactions.