1mpm
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(New page: 200px<br /><applet load="1mpm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mpm, resolution 2.6Å" /> '''MALTOPORIN MALTOSE CO...)
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Revision as of 19:29, 20 November 2007
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MALTOPORIN MALTOSE COMPLEX
Overview
BACKGROUND: Maltoporin (which is encoded by the lamB gene) facilitates the, translocation of maltodextrins across the outer membrane of E. coli. In, particular, it is indispensable for the transport of long, maltooligosaccharides, as these do not pass through non-specific porins., An understanding of this intriguing capability requires elucidation of the, structural basis. RESULTS: The crystal structures of maltoporin in complex, with maltose, maltotriose and maltohexaose reveal an extended binding site, within the maltoporin channel. The maltooligosaccharides are in apolar van, der Waals contact with the 'greasy slide', a hydrophobic path that is, composed of aromatic residues and located at the channel lining. At the, constriction of the channel the sugars are tightly surrounded by protein, side chains and form an extensive hydrogen-bonding network with ionizable, amino-acid residues. CONCLUSION: Hydrophobic interactions with the greasy, slide guide the sugar into and through the channel constriction. The, glucosyl-binding subsites at the channel constriction confer, stereospecificity to the channel along with the ability to scavenge, substrate at low concentrations.
About this Structure
1MPM is a Single protein structure of sequence from Escherichia coli with MG as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structures of various maltooligosaccharides bound to maltoporin reveal a specific sugar translocation pathway., Dutzler R, Wang YF, Rizkallah P, Rosenbusch JP, Schirmer T, Structure. 1996 Feb 15;4(2):127-34. PMID:8805519
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