Maltose metabolism in Enterococcus faecalis

MAGNI, C DEUSTCHER J, BLANCATO

Potrero de los Funes

Congreso; XLV Reunión Anual de SAIB; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Enterococcus faecalis is one of the most controversial lactic acid bacterium. This microorganism is normally present in the microflora of the animal gut but also emerged as an opportunistic pathogen in the last decade. It can also be found in cheese where improves the quality of the fermented product. In clinical E. faecalis isolates biofilm formation play an important role being this phenotype associated to maltose metabolism. The maltose cluster is organized in a divergent fashion, malPBMR operon encodes putative maltose phosphate phosphorylase (malP), â-phosphoglucomutase (malB), aldose-1-epimerase (malM) and transcriptional repressor (malR); and malT encoding for a PTS enzyme II. [14C]maltose uptake experiments in a strain with a polar interruption of malP indicated that uncharged compounds are accumulated suggesting that a specific phosphatase might still be active. Bioinformatic analysis allowed us to detect downstream from malT an ORF annotated as a phosphatase protein (mapP). A mapP deficient strain showed diminished growth in maltose supplemented media indicating a connection with the pathway. Uptake experiments in the mapP- strain revealed the accumulation of charged products (probably maltose-6P). In order to confirm their activity both enzymes were over-produced and purified from E. coli. The results presented contribute to understand the maltose metabolism of E. faecalis.