1mpm: Difference between revisions
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== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1mpm]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MPM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1MPM FirstGlance]. <br> | <table><tr><td colspan='2'>[[1mpm]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MPM OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1MPM FirstGlance]. <br> | ||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>< | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | ||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mpm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mpm OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1mpm RCSB], [http://www.ebi.ac.uk/pdbsum/1mpm PDBsum]</span></td></tr> | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mpm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mpm OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1mpm RCSB], [http://www.ebi.ac.uk/pdbsum/1mpm PDBsum]</span></td></tr> | ||
<table> | </table> | ||
== Function == | |||
[[http://www.uniprot.org/uniprot/LAMB_ECOLI LAMB_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 == | == Evolutionary Conservation == | ||
[[Image:Consurf_key_small.gif|200px|right]] | [[Image:Consurf_key_small.gif|200px|right]] | ||
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</StructureSection> | </StructureSection> | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Dutzler, R | [[Category: Dutzler, R]] | ||
[[Category: Schirmer, T | [[Category: Schirmer, T]] | ||
[[Category: Beta barrel]] | [[Category: Beta barrel]] | ||
[[Category: Membrane protein]] | [[Category: Membrane protein]] | ||
[[Category: Specific porin]] | [[Category: Specific porin]] | ||
[[Category: Sugar transport]] | [[Category: Sugar transport]] | ||
Revision as of 19:11, 25 December 2014
MALTOPORIN MALTOSE COMPLEXMALTOPORIN MALTOSE COMPLEX
Structural highlights
Function[LAMB_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 PubMedBACKGROUND: 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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