PURIFICATION, CHARACTERIZATION, AND POSSIBLE FUNCTIONS OF SMALL MOLECULAR-WEIGHT GTP-BINDING PROTEINS

GTP-binding proteins with molecular weights of approximately 20, 000 are designated small MrG proteins. We purified four small MrG proteins to near homogeneity from bovine brain crude membranes. Properties of these proteins, 20K G, 21K G, 22K G, and 24K G, were then assessed. The cDNA of 22K G and 24K G were cloned, and their nucleotide and amino acid sequences were determined. Three types of both C-terminal sequences and amino acid sequences were identified. We conclude that small MrG proteins and large MrG proteins are components of large intracellular regulatory and messenger systems with specific roles in cell function regulation. © 1990 by the American Journal of Hypertension, Ltd.