Enterococcus faecalis MalR acts as a repressor of the maltose operons and additionally mediates their catabolite repression via direct interaction with seryl‐phosphorylated‐HPr

GRAND, MAXIME; BLANCATO, VICTOR SEBASTIÁN; ESPARIZ, MARTÍN; DEUTSCHER, JOSEF; PIKIS, ANDREAS; HARTKE, AXEL; MAGNI, CHRISTIAN; SAUVAGEOT, NICOLAS

MOLECULAR MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020 vol. 113 p. 464 - 477

0950-382X

Enterococci are gram-positive pathogens and lead to cause hospital-acquiredinfections worldwide. Central carbon metabolism was shown as highly induced inEnterococcus faecalis during infection context. Metabolism of α-polysaccharides waspreviously described as an important factor for host colonisation and biofilm formation.A better characterisation of the adaptation of this bacterium to carbohydrateavailabilities may lead to a better understanding of the link between carbohydratemetabolism and the infection process of E. faecalis. Here we show that MalR, a LacI/GalR transcriptional regulator, is the main factor in the regulation of the two divergentoperons involved in maltose metabolism in this bacterium. The malR gene istranscribed from the malP promoter, but also from an internal promoter inside thegene located upstream of malR. In the absence of maltose, MalR acts as a repressorand in the presence of glucose, it exerts efficient CcpA-independent carbon cataboliterepression. The central PTS protein P-Ser-HPr interacts directly with MalR andenhances its DNA binding capacity, which allows E. faecalis to adapt its metabolismto environmental conditions.