Lactobacillus curvatus has a glucose transport system homologous to the mannose family of phosphoenolpyruvate-dependent phosphotransferase systems

Abstract

In Lactobacillus curvatus, a phosphoenolpyruvate:mannose phosphotransferase 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 PCR 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 sake impaired in EIIMan 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 protein encoded by manB could also play a regulatory role in L. curvatus.