Molecular characterization of the Lactococcus lactis ptsHI operon and analysis of the regulatory role of HPr.

ABSTRACT: The Lactococcus lactis ptsH and ptsI genes, encoding the general proteins of the phosphoenolpyruvate-dependent phosphotransferase system, HPr and enzyme I, respectively, were cloned, and the regulatory role of HPr was studied by mutational analysis of its gene. A promoter sequence was identified upstream of the ptsHI operon, and the transcription start site was mapped by primer extension. The results of Northern analyses showed the presence of two glucose-inducible transcripts, one of 0.3 kb containing ptsH and a second of 2.0 kb containing both ptsH and ptsI. Disruption of the ptsH and ptsI genes in strain NZ9800 resulted in a reduced growth rate at the expense of glucose, but no growth at the expense of sucrose and fructose, confirming the dominant role of the phosphotransferase system i

SUBMITTER: Luesink EJ 

PROVIDER: S-EPMC93441 | biostudies-literature | 1999 Feb

REPOSITORIES: biostudies-literature