PMID:12153569

Citation	Jennings, GT, Savino, S, Marchetti, E, Aricò, B, Kast, T, Baldi, L, Ursinus, A, Höltje, JV, Nicholas, RA, Rappuoli, R and Grandi, G (2002) GNA33 from Neisseria meningitidis serogroup B encodes a membrane-bound lytic transglycosylase (MltA). Eur. J. Biochem. 269:3722-31
Abstract	In a previous study, we used the genome of serogroup B Meningococcus to identify novel vaccine candidates. One of these molecules, GNA33, is well conserved among Meningococcus B strains, other Meningococcus serogroups and Gonococcus and induces bactericidal antibodies as a result of being a mimetic antigen of the PorA epitope P1.2. GNA33 encodes a 48-kDa lipoprotein that is 34.5% identical with membrane-bound lytic transglycosylase A (MltA) from Escherichia coli. In this study, we expressed GNA33, i.e. Meningococcus MltA, as a lipoprotein in E. coli. The lipoprotein nature of recombinant MltA was demonstrated by incorporation of [3H]palmitate. MltA lipoprotein was purified to homogeneity from E. coli membranes by cation-exchange chromatography. Muramidase activity was confirmed when MltA was shown to degrade insoluble murein sacculi and unsubstituted glycan strands. HPLC analysis demonstrated the formation of 1,6-anhydrodisaccharide tripeptide and tetrapeptide reaction products, confirming that the protein is a lytic transglycosylase. Optimal muramidase activity was observed at pH 5.5 and 37 degrees C and enhanced by Mg2+, Mn2+ and Ca2+. The addition of Ni2+ and EDTA had no significant effect on activity, whereas Zn2+ inhibited activity. Triton X-100 stimulated activity 5.1-fold. Affinity chromatography indicated that MltA interacts with penicillin-binding protein 2 from Meningococcus B, and, like MltA from E. coli, may form part of a multienzyme complex.
Links	PubMed
Keywords	Amino Acid Sequence; Base Sequence; Chromatography, Affinity; Cloning, Molecular; Escherichia coli/genetics; Glycosyltransferases/genetics; Glycosyltransferases/metabolism; Kinetics; Lipoproteins/genetics; Lipoproteins/metabolism; Membrane Proteins/metabolism; Molecular Sequence Data; Muramidase/metabolism; Neisseria meningitidis/classification; Neisseria meningitidis/enzymology; Neisseria meningitidis/genetics; Peptidoglycan/metabolism; Recombinant Proteins/genetics; Recombinant Proteins/isolation & purification; Recombinant Proteins/metabolism; Serotyping; Substrate Specificity
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
NEIME:Q9JPQ6		GO:0008933: lytic transglycosylase activity	ECO:0000314:		F		Figure 5. HPLC analysis demonstrated the formation of 1,6-anhydrodisaccharide tripeptide and tetrapeptide reaction products, confirming that the protein is a lytic transglycosylase	complete CACAO 12189

References

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