A Light Scattering Study of the Interaction of Fibroblast Growth Factor (FGF) with its Receptor
Pallavi Sharma 1, Dakshinamurthy Rajalingam 2, Thallapuranam Krishnaswamy Suresh Kumar 2* and Surender Singh 2
1 drpallavi1978@gmail.com
2 University of Arkansas, Fayetteville, AR 72701
* To whom correspondence should be addressed. E-mail: sthalla{at}uark.edu.
Submitted on January 15, 2008
Revised on January 18, 2008
Accepted on 8 February 2008
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Abstract |
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ABSTRACT Light scattering technique has been used to study the interaction between fibroblast growth factor (FGF), and its receptor. In this study, a general mathematical model has been developed where the concentration of product formed by the interaction of two proteins and its dependence on the initial concentration of interacting proteins have been determined using laser light scattering. Calculated hydrodynamic diameters reveal that both human fibroblast growth factor (hFGF-1), and its receptor domain (D2 domain), exist as monomers in solution. Titration of hFGF-1 and the D2 domain of FGFR, show that they interact in a 1:1 stoichiometry in solution. The binding stoichiometry does not depend on the concentrations of the interacting proteins. The results of this study, for the first time, provide an unambiguous evidence that the 2:2 binary complex of FGF and FGFR observed in the crystal structures of the FGF-FGFR complex (in the absence of heparin) is possibly a crystallization artifact.
Key Words:
interaction, isothermal titration calorimetry, light scattering, protein, stoichiometry
