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Phospholipid substitution of capsular polysaccharides and mechanisms of capsule formation in Neisseria meningitidis
Author(s) -
Frosch Matthias,
Müller Astrid
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01592.x
Subject(s) - biology , polysaccharide , biochemistry , bacterial capsule , phospholipid , atp binding cassette transporter , escherichia coli , neisseria meningitidis , molecular mass , size exclusion chromatography , gene , microbiology and biotechnology , bacteria , transporter , virulence , genetics , membrane , enzyme
Summary Within the capsule gene complex ( cps ) of Neisseria meningitidis two functional regions B and C are involved in surface translocation of the cytoplasmically synthesized capsular polysaccharide, which is a homopolymer of α‐2,8 polyneuraminic acid. The region‐C gene products share characteristics with transporter proteins of the ABC (ATP‐binding cassette) superfamily of active transporters. For analysis of the role of region B in surface translocation of the capsular polysaccharide we purified the polysaccharides of region B‐ and region C‐defective Escherichia coli clones by affinity chromatography. The molecular weights of the polysaccharides were determined by gel filtration and the polysaccharides were analysed for phospholipid substitution by polyacrylamide gel electrophoresis and immunoblotting. The results indicate that the full‐size capsular polysaccharide with a phospholipid anchor is synthesized intracellularly and that lipid modification is a strong requirement for translocation of the poly saccharide to the cell surface. Proteins encoded by region B are involved in phospholipid substitution of the capsular polysaccharide. Nucleotide sequence analysis of region B revealed two open reading frames, which encode proteins with molecular masses of 45.1 and 48.7 kDa.