Functional homology of Bacillus subtilis methyltransferase II and Escherichia coli cheR protein.

A chemotaxis-related methyltransferase enzyme from Bacillus subtilis has been shown to methylate membrane-bound proteins in Escherichia coli in vitro. The methylated proteins are in the same molecular weight range as authentic E. coli methyl-accepting chemotaxis proteins. It was also shown that wild type E. coli cytoplasmic extract could methylate membrane proteins from B. subtilis in its methyl-accepting chemotaxis protein region. Cytoplasmic extracts from methyltransferase mutants of either species could methylate neither set of methyl-accepting proteins in vitro. The B. subtilis enzyme was incapable of methylating any of a group of soluble eucaryotic proteins. These data suggest functional homology between B subtilis methyltransferase II and E. coli cheR protein (chemotaxis methyltransferase) despite the evolutionary divergence between these two species.