BIOCHEMICAL-EVIDENCE THAT SACCHAROMYCES-CEREVISIAE YGR262C GENE, REQUIRED FOR NORMAL GROWTH, ENCODES A NOVEL SER THR-SPECIFIC PROTEIN/

Saccharomyces cerevisiae YGR262c gene, whose disruption causes severel y defective growth, encodes a putative protein kinase shorter than any other protein kinase biochemically characterized to date and lacking some of the conserved features of these enzymes, Here we show that the product of the YGR262c gene, piD261, expressed in E. coli with a C-te rminal (His)(6) tag, is a bona fide Ser/Thr protein kinase as judged f rom its capability to autophosphorylate and to phosphorylate casein an d osteopontin in the presence of [gamma-P-32]ATP, In contrast, no phos phorylation of histones, myelin basic protein, phosvitin, bovine serum albumin and poly(Glu/Tyr)4:1 could be detected, Mn2+ or, less effecti vely, Co2+ are required for piD261 catalytic activity, which is conver sely undetectable in the presence of Mg2+, a behaviour unique among Se r/Thr protein kinases. (C) 1997 Federation of European Biochemical Soc ieties.