Dynamic properties of the guanine nucleotide binding protein alpha subunit and comparison of its guanosine triphosphate hydrolase domain with that of ras p21.

The dynamic properties of the alpha-subunit of bovine transducin (Galphat) were studied using molecular dynamics simulations and essential dynamics analyses. The helical domain of transducin seems to move toward the guanosine triphosphate hydrolase (GTPase) domain. Our studies suggest that this movement is facilitated by a hinge bending motion that is centered on residues Gly56 and Gly179 and that this motion may be involved in GDP release and GTP hydrolysis. The dynamic properties of the GTPase domain of Galphat-GDP were compared to those of ras p21 and reveal a significant degree of similarity, indicating common dynamic properties for an equivalent domain in two different proteins.