Maltose utilization in Enterococcus faecalis.
OBJECTIVE
The aim of this research was to characterize the metabolic pathway for maltose utilization in Enterococcus faecalis.


RESULTS
Screening a library of Enterococcus faecalis insertional mutants allowed the isolation of mutants affected in maltose utilization. Genetic analysis of the insertion loci revealed insertions in neighbour genes encoding an EII component of a phosphotransferase system (PTS) transporter (malT) and a maltose phosphorylase homologue (malP). The malP gene forms part of an operon which also includes genes encoding a phosphoglucomutase (malB), a mutarotase (aldose 1-epimerase) (malM) and a transcriptional regulator (malR). Analysis of (14)C-labelled carbohydrates uptake revealed that more than 97% of maltose enters the cells by the PTS transporter MalT.


CONCLUSIONS
Both experimental data and genetic organization of the malPBMR operon strongly suggest that in Enterococcus faecalis, maltose enters using a PTS, leaving maltose-6-phosphate inside the cells which is hydrolysed by a maltose phosphate phosphorylase (MalP).


CONCLUSIONS
This study describes a new pathway for maltose utilization in lactic acid bacteria.
Le Breton
Y
Y
Laboratoire de Microbiologie de l'Environnement, USC INRA, IRBA, Université de Caen, 14032 Caen Cedex, France.
Pichereau
V
V
Sauvageot
N
N
Auffray
Y
Y
Rincé
A
A
D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics / Q000502:physiology; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005798:Genes, Bacterial / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism; D008320:Maltose / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010770:Phosphotransferases / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D008320:Maltose; D005964:Glucosyltransferases; C021535:maltose phosphorylase; D010770:Phosphotransferases; D005947:Glucose