Type 3-specific synthase of Streptococcus pneumoniae (Cap3B) directs type 3 polysaccharide biosynthesis in Escherichia coli and in pneumococcal strains of different serotypes

J Exp Med. 1996 Aug 1;184(2):449-55. doi: 10.1084/jem.184.2.449.

Abstract

The cap3B gene, which is involved in the formation of the capsule of Streptococcus pneumoniae type 3, encodes a 49-kD protein that has been identified as a polysaccharide synthase. Escherichia coli cells harboring the recombinant plasmid pTBP3 (cap3B) produced pneumococcal type 3 polysaccharide, as demonstrated by immunological tests. Biochemical and cell fractionation analyses revealed that this polysaccharide had a high molecular mass and was localized in substantial amounts in the periplasmic space of E. coli. Unencapsulated (S-2), laboratory pneumococcal strains synthesized type 3 polysaccharide by transformation with plasmid pLSE3B harboring cap3B. In addition, encapsulated pneumococci of types 1, 2, 5, or 8 transformed with pLSE3B can direct the synthesis of pneumococcal type 3 polysaccharide, leading to the formation of strains that display binary type of capsule.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Capsules / biosynthesis*
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers / chemistry
  • DNA, Bacterial / genetics
  • Escherichia coli
  • Genes, Bacterial
  • Glycosyltransferases / genetics*
  • Ligases / genetics*
  • Molecular Sequence Data
  • Restriction Mapping
  • Streptococcus pneumoniae / enzymology*

Substances

  • Bacterial Proteins
  • DNA Primers
  • DNA, Bacterial
  • Cap3B protein, Streptococcus pneumoniae
  • Glycosyltransferases
  • Ligases