2wjr
From Proteopedia
NanC porin structure in rhombohedral crystal form.
Structural highlights
FunctionNANC_ECOLI Outer membrane channel protein allowing the entry of N-acetylneuraminic acid (Neu5Ac, the most abundant sialic acid on host cell surfaces) into the bacteria (Probable). NanC proteins form high-conductance channels which are open at low membrane potentials and which have a weak anion selectivity.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSialic acids are acidic sugars present mostly on vertebrate cell surfaces, which can be metabolized by bacteria and act as an inflammation signal. N-Acetylneuraminic acid, the most abundant sialic acid, can enter into Escherichia coli K12 through NanC, an N-acetylneuraminic acid-inducible outer-membrane channel. With its 215 residues, NanC belongs to the family of small monomeric KdgM-related porins. KdgM homologues are found in gammaproteobacteria, including major plant and human pathogens, and together they define a large family of putative acidic sugar/oligosaccharide transporters, which are as yet poorly characterized. Here, we present the first high-resolution structure of a KdgM family member. NanC folds into a 28-A-high, 12-stranded beta-barrel, resembling the beta-domain of autotransporter NalP and defining an open pore with an average radius of 3.3 A. The channel is lined by two strings of basic residues facing each other across the pore, a feature that appears largely conserved within the KdgM family and is likely to facilitate the diffusion of acidic oligosaccharides. NanC crystal structure, a model for outer-membrane channels of the acidic sugar-specific KdgM porin family.,Wirth C, Condemine G, Boiteux C, Berneche S, Schirmer T, Peneff CM J Mol Biol. 2009 Dec 11;394(4):718-31. Epub 2009 Sep 29. PMID:19796645[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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