Molecular cloning and functional characterization of components of the capsule biosynthesis complex of Neisseria meningitidis serogroup A: toward in vitro vaccine production

Timm Fiebig, Friedrich Freiberger, Vittoria Pinto, Maria Rosaria Romano, Alan Black, Christa Litschko, Andrea Bethe, Dmitry Yashunsky, Roberto Adamo, Andrei Nikolaev, Francesco Berti, Rita Gerardy-Schahn

    Research output: Contribution to journalArticlepeer-review

    28 Citations (Scopus)


    The human pathogen Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis and sepsis globally. A major virulence factor of Nm is the capsular polysaccharide (CPS), which in Nm serogroup A consists of N-acetyl-mannosamine-1-phosphate units linked together by phosphodiester linkages [?6)-a-D-ManNAc-(1?OPO3-?]n . Acetylation in O-3 (to a minor extent in O-4) position results in immunologically active polymer. In the capsule gene cluster (cps) of Nm, region A contains the genetic information for CPSA biosynthesis. Thereby the open reading frames csaA, -B, and -C are thought to encode the UDP-N-acetyl-D- glucosamine-2-epimerase, poly-ManNAc-1-phosphate-transferase, and O-acetyltransferase, respectively. With the aim to use a minimal number of recombinant enzymes to produce immunologically active CPSA, we cloned the genes csaA, csaB, and csaC and functionally characterized the purified recombinant proteins. If recombinant CsaA and CsaB were combined in one reaction tube, priming CPSA-oligosaccharides were efficiently elongated with UDP-GlcNAc as the donor substrate, confirming that CsaA is the functional UDP-N-acetyl-D- glucosamine-2-epimerase and CsaB the functional poly-ManNAc-1-phosphate- transferase. Subsequently, CsaB was shown to transfer ManNAc-1P onto O-6 of the non-reducing end sugar of priming oligosaccharides, to prefer non-O-acetylated over O-acetylated primers, and to efficiently elongate the dimer of ManNAc-1-phosphate. The in vitro synthesized CPSA was purified, O-acetylated with recombinant CsaC, and proven to be identical to the natural CPSA by 1H NMR, 31P NMR, and immunoblotting. If all three enzymes and their substrates were combined in a one-pot reaction, nature identical CPSA was obtained. These data provide the basis for the development of novel vaccine production protocols.

    Original languageEnglish
    Pages (from-to)19395-19407
    Number of pages13
    JournalJournal of Biological Chemistry
    Issue number28
    Publication statusPublished - 11 Jul 2014

    Fingerprint Dive into the research topics of 'Molecular cloning and functional characterization of components of the capsule biosynthesis complex of <em>Neisseria meningitidis</em> serogroup A: toward in vitro vaccine production'. Together they form a unique fingerprint.

    Cite this