Document Type
Article
Publication Date
11-2011
Source Publication
Journal of Molecular Biology
Abstract
We have recently discovered an allosteric switch in Ras, bringing an additional level of complexity to this GTPase whose mutants are involved in nearly 30% of cancers. Upon activation of the allosteric switch, there is a shift in helix 3/loop 7 associated with a disorder to order transition in the active site. Here, we use a combination of multiple solvent crystal structures and computational solvent mapping (FTMap) to determine binding site hot spots in the “off” and “on” allosteric states of the GTP-bound form of H-Ras. Thirteen sites are revealed, expanding possible target sites for ligand binding well beyond the active site. Comparison of FTMaps for the H and K isoforms reveals essentially identical hot spots. Furthermore, using NMR measurements of spin relaxation, we determined that K-Ras exhibits global conformational dynamics very similar to those we previously reported for H-Ras. We thus hypothesize that the global conformational rearrangement serves as a mechanism for allosteric coupling between the effector interface and remote hot spots in all Ras isoforms. At least with respect to the binding sites involving the G domain, H-Ras is an excellent model for K-Ras and probably N-Ras as well. Ras has so far been elusive as a target for drug design. The present work identifies various unexplored hot spots throughout the entire surface of Ras, extending the focus from the disordered active site to well-ordered locations that should be easier to target.
Recommended Citation
Buhrman, Greg; O'Connor, Casey; Zerbe, Brandon; Kearney, Bradley M.; Napoleon, Raeanne; Kovrigina, Elizaveta A.; Vajda, Sandor; Kozakov, Dima; Kovriguine, Evgueni; and Mattos, Carla, "Analysis of Binding Site Hot Spots on the Surface of Ras GTPase" (2011). Chemistry Faculty Research and Publications. 224.
https://epublications.marquette.edu/chem_fac/224
Comments
Accepted version. Journal of Molecular Biology, Vol. 413, No. 4 (November 2011): 773-789. DOI. © 2011 Elsevier Ltd. Used with permission.
Elizaveta A. Kovrigina was affiliated with Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC and Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI at the time of publication.
Evgenii L. Kovrigine was affiliated with Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI and Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC at the time of publication.