Specific in vitro guanylylation of a 43-kilodalton membrane-associated protein of Streptomyces coelicolor

Abstract

Incubation of [alpha-32P]GTP with cellular extracts or membranes of Streptomyces coelicolor labels a protein of 43 kDa, which was also labeled with [8,5'-3H]GTP but not with [alpha-32P]ATP or [gamma-32P]GTP. Radioactivity remained associated with this protein after boiling in 0.1 N NaOH, but it was dissociated after incubation in 0.1 N HCl or hydroxylamine. Chromatographic analysis of the HCl-dissociated compound showed that GMP was the covalently bound nucleotide. Furthermore, guanylylation appeared to be reversible and to take place by a pyrophosphorylytic mechanism. Guanylylation was more efficient at low temperatures. Several Streptomyces species showed a guanylylated protein with a similar molecular mass.

Proteins that interact with GTP in Streptomyces griseus and its possible implication in morphogenesis

“…In agreement with this suggestion, in S. coelicolor a protein with ihe same molecular size (43 kDa) is reported to be guanylylated [6].…”

“…As examined for cells grown on GYM agar plate (Fig. 3), there are considerable differences in labelling pattern between cells prepared from different growth phase, a result consistent with previous works with B. subtilis [7] and 5. coelicolor [6]. Similar changes in labelling pattern were detected when cells were grown in liquid (GYM) medium instead of GYM agar plate.…”

“…The existence of GTPbinding protein is also suggested recently in Streptomyces coelicolor A3(2) [6]. In addition to the GTPbinding to proteins, guanylylation of proteins was demonstrated in B. subtilis [7] and S. caelicolor A3(2) [6]. Existence of phosphorylated proteins in S. coelicolor and Streptomyces griseus is also i-eported…”

“…The Obg protein is another GTP-binding protein which was found in Bacillus subtilis, belongs to the GTPase superfamily of proteins and is indispensable for the cell [S]. The existence of GTPbinding protein is also suggested recently in Streptomyces coelicolor A3(2) [6]. In addition to the GTPbinding to proteins, guanylylation of proteins was demonstrated in B. subtilis [7] and S. caelicolor A3(2) [6].…”