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MALTOPORIN SUCROSE COMPLEX
Structural highlights
FunctionLAMB_ECOLI Involved in the transport of maltose and maltodextrins, indispensable for translocation of dextrins containing more than three glucosyl moieties. A hydrophobic path ("greasy slide") of aromatic residues serves to guide and select the sugars for transport through the channel. Also acts as a receptor for several bacteriophages including lambda.[HAMAP-Rule:MF_01301] 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 PubMedMaltoporin (LamB) facilitates the diffusion of maltodextrins across the outer membrane of E. coli. The structural basis for the specificity of the channel is investigated by X-ray structure analysis of maltoporin in complex with the disaccharides sucrose, trehalose, and melibiose. The sucrose complex, determined to 2.4 A resolution, shows that the glucosyl moiety is partly inserted into the channel constriction, while the bulky fructosyl residue appears to be hindered to enter the constriction, thus interfering with its further translocation. One of the glucosyl moieties of trehalose is found in a similar position as the glucosyl moiety of sucrose, whereas melibiose appears disordered when bound to maltoporin. A comparison with the previously reported maltoporin-maltose complex sheds light on the basis for sugar discrimination, and explains the different permeation rates observed for the saccharides. Channel specificity: structural basis for sugar discrimination and differential flux rates in maltoporin.,Wang YF, Dutzler R, Rizkallah PJ, Rosenbusch JP, Schirmer T J Mol Biol. 1997 Sep 12;272(1):56-63. PMID:9299337[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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