BIOPHYSICAL THEORY AND MODELING |
Mutations Affecting the Oligomerization Interface of G-Protein Coupled Receptors Revealed by a Novel De-novo Protein Design Framework
Martin S Taylor 1, Ho K Fung 1, Rohit Rajgaria 1, Marta Filizola 2, Harel Weinstein 2 and Christodoulos A Floudas 1*
1 Princeton University
2 Weill Medical College of Cornell University
* To whom correspondence should be addressed. E-mail: floudas{at}titan.princeton.edu.
Submitted on July 18, 2007
Revised on October 9, 2007
Accepted on 1 November 2007
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Abstract |
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Specific functional and pharmacological properties have recently been ascribed to G-Protein Coupled Receptor (GPCR) dimers/oligomers. Because the association of two identical or two distinct GPCR monomers seems to be required to elicit receptor function, it is necessary to understand the exact nature of this interaction. We present here a novel method for de novo protein design and its application to the prediction of mutations that can stabilize or destabilize a GPCR dimer while maintaining the monomer's native fold. To test the efficacy of this new method, the dimer of the single-spanned transmembrane domain of glycophorin A was used as a model system. Experimental data from mutagenesis of the helix-helix interface are compared with computational predictions at that interface, and the model's results are found to be consistent with the experimental findings. A flexible template was developed for the rhodopsin homodimer at atomic resolution and used to predict sets of three and five mutations. The results are found to be consistent across eight case studies, with favored mutations at each position. Mutations sets predicted to be the most disruptive at the dimerization interface are found to be less specific to the flexible template than sets predicted to be less disruptive.
Key Words:
G-protein coupled receptor, de-novo protein design, dimerization, flexible templates, helix-helix interface, rhodopsin
