Structure of the OmpA-like domain of RmpM from Neisseria meningitidis.
RmpM is a putative peptidoglycan binding protein from Neisseria meningitidis that has been shown to interact with integral outer membrane proteins such as porins and TonB-dependent transporters. Here we report the 1.9 A crystal structure of the C-terminal domain of RmpM. The 150-residue domain adopts a betaalphabetaalphabetabeta fold, as first identified in Bacillus subtilis chorismate mutase. The C-terminal RmpM domain is homologous to the periplasmic, C-terminal domain of Escherichia coli OmpA; these domains are thought to be responsible for non-covalent interactions with peptidoglycan. From the structure of the OmpA-like domain of RmpM, we suggest a putative peptidoglycan binding site and identify residues that may be essential for binding. Both the crystal structure and solution experiments indicate that RmpM may exist as a dimer. This would promote more efficient peptidoglycan binding, by allowing RmpM to interact simultaneously with two glycan chains through its C-terminal, OmpA-like binding domain, while its (structurally uncharacterized) N-terminal domain could stabilize oligomers of porins and TonB-dependent transporters in the outer membrane.
Grizot
Sylvestre
S
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Department of Health and Human Services, Bethesda, Maryland 20892, USA.
Buchanan
Susan K
SK
D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000737:chemistry*; D001412:Bacillus subtilis / Q000201:enzymology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D002826:Chorismate Mutase / Q000737:chemistry; D018360:Crystallography, X-Ray; D019281:Dimerization; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000737:chemistry*; D010457:Peptidoglycan / Q000378:metabolism; D018272:Porins / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D040681:Structural Homology, Protein
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D010457:Peptidoglycan; D018272:Porins; D021122:Protein Subunits; C499670:RmpM protein, Neisseria; C078167:OMPA outer membrane proteins; D002826:Chorismate Mutase