LACTOBACILLUS CURVATUS HAS A GLUCOSE-TRANSPORT SYSTEM HOMOLOGOUS TO THE MANNOSE FAMILY OF PHOSPHOENOLPYRUVATE-DEPENDENT PHOSPHOTRANSFERASE SYSTEMS

In Lactobacillus curvatus, a phosphoenolpyruvate :mannose phosphotrans ferase system (mannose-PTS) has been characterized and it was shown to be involved in glucose and mannose transport, but no glucose-specific PTS activity could be detected, A 2.1 kb DNA fragment amplified by PC R from the L. curvatus genome was sequenced. Sequence analysis showed four ORFs which could encode proteins similar to PTS transporters EIIA , EIIB, EIIC and EIID of the mannose class. The expression of the manB gene (encoding EIIB) from L. curvatus in a mutant of Lactobacillus sa ke impaired in EII(Man) activity restored this activity. Furthermore, this DNA fragment complemented the regulatory function of LevE (EIIB) in a Bacillus subtilis levE-deficient mutant, suggesting that the prot ein encoded by manB could also play a regulatory role in L. curvatus.