Two open reading frames adjacent to the Escherichia coli K-12 transketolase (tkt) gene show high similarity to the mannitol phosphotransferase system enzymes from Escherichia coli and various gram-positive bacteria

Abstract

I have subcloned and sequenced the genes cmtB and cmtA of Escherichia coli K-12 which lie adjacent to the tkt gene on the chromosome. The genes cmtB and cmtA could encode a cytoplasmic protein (EIIA) and an integral-membrane protein (EIIBC), respectively, of the bacterial phospho enol pyruvate-dependent carbohydrate phosphotransferase system. High similarity to the Enzymes IIMtl of Escherichia coli K-12 (gene mtlA) and of Staphylococcus carnosus was detected, but the two genes did not complement mannitol-negative E. coli mutants without the use of a heterologous promoter.