Interaction of GTP with proteins during the cell cycle of Streptomyces coelicolor

Abstract Six putative GTP binding proteins were detected by ultraviolet light in the presence of α-³²P]GTP during the developmental cycle of Streptomyces coelicolor . Four out of six were true GTP binding proteins. Immunological reactions carried out with antiserum which recognizes the α-common subunit of G regulatory proteins identified two bands of 67 kDa and 30 kDa. Studies with γ-³²P]GTP showed significant changes in protein phosphorylation during the cell cycle. The results show that at least three different systems of GTP protein interaction are present in S. coelicolor .