Identification of a genetic locus involved in the biosynthesis of N-acetyl-D-mannosamine, a precursor of the (alpha 2-->8)-linked polysialic acid capsule of serogroup B Neisseria meningitidis.

We characterized the genetic defect of a capsule-deficient serogroup B meningococcal strain created by Tn916 mutagenesis. The transposon insertion interrupts a capsule biosynthesis gene, synX, which is involved in the production of N-acetyl-D-mannosamine, a precursor of the (alpha 2-->8)-linked polysialic acid capsule of serogroup B meningococci.