View source for 1mpn


==MALTOPORIN MALTOTRIOSE COMPLEX==
<StructureSection load='1mpn' size='340' side='right'caption='[[1mpn]], [[Resolution|resolution]] 3.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1mpn]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MPN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MPN FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1mpn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mpn OCA], [https://pdbe.org/1mpn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mpn RCSB], [https://www.ebi.ac.uk/pdbsum/1mpn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mpn ProSAT]</span></td></tr>
</table>
== Function ==
[https://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 ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/mp/1mpn_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1mpn ConSurf].
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== Publication Abstract from PubMed ==
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.

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<ref>PMID:8805519</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1mpn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Porin 3D structures|Porin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Dutzler R]]
[[Category: Schirmer T]]