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Conformational and binding properties of chicken liver basic fatty acid binding protein in solution
Author(s) -
Schievano Elisabetta,
Quarzago Daniela,
Spadon Paola,
Monaco Hugo Luis,
Zanotti Giuseppe,
Peggion Evaristo
Publication year - 1994
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360340707
Subject(s) - chemistry , chicken liver , biochemistry , fatty acid binding protein , plasma protein binding , biophysics , enzyme , gene , biology
The conformation of basic fatty acid binding protein from chicken liver and the binding properties of the apo protein toward 11‐dansylamino‐undecanoic acid were investigated by CD and fluorescence spectroscopy. In one set of experiments the binding process was followed by the appearance of induced optical activity in the absorption region of the dansyl chromophore. In a second set of experiments the binding process was followed by the large enhancement of emission fluorescence of the dansyl fluorophore. From the saturation curves, the stoichiometry of the complex and the binding constant of the fatty acid to the protein were precisely determined. The values of the dissociation constant determined with the two methods were in excellent agreement: we obtained K D = (1.0 ± 0.1) · 10 −6 M in a 0.9 : 1 stoichiometry. The native conformation of the protein is remarkably stable in a variety of solvent systems, including acetonitrile–water, ethylene glycol–water, and dicxane–water of various compositions. The CD results also showed that the binding of the fatty acid does not induce any appreciable change in the protein conformation. In a mixture of water and 2,2,2‐trifluoroethanol 1 : 9 (v/v), the native conformation collapses and a new ordered structure is formed, characterized by a high amount of α‐helix. © 1994 John Wiley & Sons, Inc.