2 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

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 phosphoenolpyruvate-dependent carbohydrate phosphotransferase system. High similarity to the Enzymes II(Mtl) 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.