Capsule polysaccharides

The capsule polysaccharide (CPS) produced by Streptococcus pneumoniae is a key virulence factor that confers resistance to Complement and phagocytosis, and impacts on colonisation and system invasion.

The biosynthesis and regulation of S. pneumoniae CPS production, and role of CPS  in virulence is being investigated in collaboration with Prof. James Paton and Dr. Judy Morona.

We are study CPSs with a complex repeat unit structure, and the biosynthesis of these CPSs has much in common with lipopolysaccharide O antigen biosynthesis.

Relevant publications (since 1997)

Morona, J.K., Morona, R., and Paton, J.C. (1997) “Analysis of the genes encoding biosynthesis of type 19F capsule from Streptococcus pneumoniae”. Mol. Microbiol. 23: 751-763.

Paton, J.C., Morona, J.K., and Morona, R. (1997) “Characterisation of the capsular polysaccharide biosynthesis locus of Streptococcus pneumoniae type 19F”. Microbial Drug Resistance 3: 89-99.

Coffey, T.J., Enright, M.C., Daniels, M., Morona, J.K., Morona, R., Hryniewicz, V., Paton, J.C., and Spratt, B.G. (1998) “Recombinational exchanges at the capsular polysaccharide biosynthetic locus lead to frequent serotype changes among natural isolates of Streptococcus pneumoniae”. Mol. Microbiol. 27: 73-84.

Morona, J.K., Miller, D.C., Coffey, T.J., Vinurampulee, C.J., Spratt, B.G., Morona, R., and Paton, J.C. (1999) “Molecular and genetic characterisation of the capsule biosynthesis locus of Streptococcus pneumoniae type 23F.” Microbiol. 145: 781-789

Morona, J.K., Morona, R. and Paton, J.C. (1999) “Analysis of the 5’ portion of the type 19A capsule locus identifies two classes of cpsC, cpsD and cpsE genes in Streptococcus pneumoniae.” J. Bacteriol. 181: 3599-3605

Morona, J.K., Paton, J., Miller, D., and Morona, R. (2000) “Tyrosine phosphorylation of CpsD negatively regulates capsule polysaccharide production in Streptococcus pneumoniae. ” Mol. Microbiol. 35: 1431-1442

Morona, J.K. Morona, R., Miller, D.C., and Paton, J.C. (2002) “The Streptococcus pneumoniae capsule biosynthesis protein CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase.” J. Bacteriol. 184: 577-583.

Morona, J.K., Morona, R., Miller, D.C., and Paton, J.C. (2003) "Mutational analysis of the carboxy-terminal [YGX]4 repeat domain of CpsD, an autophosphorylating tyrosine kinase required for capsule biosynthesis in Streptococcus pneumoniae."  J. Bacteriol. 185: 3009-3019.

Morona, J.K., Miller, D.C., Morona, R., and James C. Paton, J.C. (2004) "The effect of mutations in the conserved genes cps2A, cps2B and cps2D on virulence in Streptococcus pneumoniae." J. Infect. Dis. 189:1905-1913.

Morona, J.K., Morona, R., Paton, J.C. (2006) "Attachment of capsular polysaccharide to the cell wall of Streptococcus pneumoniae type 2 is required for invasive disease." Proc Natl Acad Sci U. S. A. 103: 8505-8510.