Reduced lysis upon growth of Lactococcus lactis on galactose is a consequence of decreased binding of the autolysin AcmA.
When Lactococcus lactis subsp. lactis IL1403 or L. lactis subsp. cremoris MG1363 is grown in a medium with galactose as the carbon source, the culture lyses to a lesser extent in stationary phase than when the bacteria are grown in a medium containing glucose. Expression of AcmA, the major autolysin of L. lactis, is not influenced by the carbon source. Binding studies with a fusion protein consisting of the MSA2 protein of Plasmodium falciparum and the C-terminal peptidoglycan-binding domain of AcmA revealed that cell walls of cells from both subspecies grown on galactose bind less AcmA than cell walls of cells grown on glucose. Cells grown on glucose or galactose and treated with trichloroacetic acid prior to AcmA binding bind similar amounts of AcmA. Analysis of the composition of the lipoteichoic acids (LTAs) of L. lactis IL1403 cells grown on glucose or galactose showed that the LTA composition is influenced by the carbon source: cells grown on galactose contain LTA with less galactose than cells grown on glucose. In conclusion, growth of L. lactis on galactose changes the LTA composition in the cell wall in such a way that less AcmA is able to bind to the peptidoglycan, resulting in a decrease in autolysis.
Steen
Anton
A
Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
Buist
Girbe
G
Kramer
Naomi E
NE
Jalving
Ruud
R
Benus
Germaine F J D
GF
Venema
Gerard
G
Kuipers
Oscar P
OP
Kok
Jan
J
D001329:Autolysis; D001433:Bacteriolysis; D001483:Base Sequence; D002473:Cell Wall / Q000187:drug effects / Q000502:physiology*; D004269:DNA, Bacterial / Q000235:genetics; D005690:Galactose / Q000378:metabolism*; D007700:Kinetics; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000378:metabolism*; D010457:Peptidoglycan / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011485:Protein Binding; D015183:Restriction Mapping
D004269:DNA, Bacterial; D010457:Peptidoglycan; C092497:AcmA protein, Lactococcus lactis; D009113:Muramidase; D005690:Galactose