Cellular Mn/Zn Ratio Influences Phosphoglucomutase Activity and Capsule Production in Streptococcus pneumoniae D39
Averi L. McFarland, Nabin Bhattarai, Merrin Joseph, Malcolm E. Winkler, Julia E. Martin
Abstract
Evolving evidence strongly indicates that maintenance of metal homeostasis is essential for establishing colonization and continued growth of bacterial pathogens in the vertebrate host. In this study, we demonstrate the impact of cellular manganese/zinc (Mn/Zn) ratios on bacterial capsular polysaccharide (CPS) production, an important virulence determinant of many human-pathogenic bacteria, including Streptococcus pneumoniae. We show that higher Mn/Zn ratios increase CPS production via the Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway. The findings provide a direct role for Mn/Zn homeostasis in the regulation of CPS expression levels and further support the ability of metal cations to act as important cellular signaling mediators in bacteria.