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1n3w

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(New page: 200px<br /><applet load="1n3w" size="450" color="white" frame="true" align="right" spinBox="true" caption="1n3w, resolution 2.60&Aring;" /> '''Engineered High-Affi...)
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[[Image:1n3w.jpg|left|200px]]<br /><applet load="1n3w" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1n3w, resolution 2.60&Aring;" />
 
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'''Engineered High-Affinity Maltose-Binding Protein'''<br />
 
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==Overview==
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==Engineered High-Affinity Maltose-Binding Protein==
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The affinity of maltose-binding protein (MBP) for maltose and related, carbohydrates was greatly increased by removal of groups in the interface, opposite the ligand binding cleft. The wild-type protein has a KD of 1200, nM for maltose; mutation of residues Met-321 and Gln-325, both to alanine, resulted in a KD for maltose of 70 nM; deletion of 4 residues, Glu-172, Asn-173, Lys-175, and Tyr-176, which are part of a poorly ordered loop, results in a KD for maltose of 110 nM. Combining the mutations yields an, increased affinity for maltodextrins and a KD of 6 nM for maltotriose., Comparison of ligand binding by the mutants, using surface plasmon, resonance spectroscopy, indicates that decreases in the off-rate are, responsible for the increased affinity. Small-angle x-ray scattering was, used to demonstrate that the mutations do not significantly affect the, solution conformation of MBP in either the presence or absence of maltose., The crystal structures of selected mutants showed that the mutations do, not cause significant structural changes in either the closed or open, conformation of MBP. These studies show that interactions in the interface, opposite the ligand binding cleft, which we term the "balancing, interface," are responsible for modulating the affinity of MBP for its, ligand. Our results are consistent with a model in which the ligand-bound, protein alternates between the closed and open conformations, and removal, of interactions in the balancing interface decreases the stability of the, open conformation, without affecting the closed conformation.
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<StructureSection load='1n3w' size='340' side='right'caption='[[1n3w]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1n3w]] is a 1 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=1N3W OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1N3W FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.6&#8491;</td></tr>
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<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=PRD_900001:alpha-maltose'>PRD_900001</scene></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1n3w FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1n3w OCA], [https://pdbe.org/1n3w PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1n3w RCSB], [https://www.ebi.ac.uk/pdbsum/1n3w PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1n3w ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/MALE_ECOLI MALE_ECOLI] Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides.
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/n3/1n3w_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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=1n3w ConSurf].
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<div style="clear:both"></div>
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==About this Structure==
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==See Also==
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1N3W is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MAL as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1N3W OCA].
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*[[Maltose-binding protein 3D structures|Maltose-binding protein 3D structures]]
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__TOC__
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==Reference==
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</StructureSection>
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Insights into the conformational equilibria of maltose-binding protein by analysis of high affinity mutants., Telmer PG, Shilton BH, J Biol Chem. 2003 Sep 5;278(36):34555-67. Epub 2003 Jun 6. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12794084 12794084]
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[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
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[[Category: Single protein]]
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[[Category: Large Structures]]
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[[Category: Shilton, B.H.]]
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[[Category: Shilton BH]]
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[[Category: Telmer, P.G.]]
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[[Category: Telmer PG]]
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[[Category: MAL]]
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[[Category: engineered]]
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[[Category: high-affinity mutant]]
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[[Category: maltose-binding protein]]
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[[Category: mbp]]
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[[Category: mbpdel]]
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[[Category: mbpdel-liganded]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 21:56:22 2007''
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Current revision

Engineered High-Affinity Maltose-Binding Protein

PDB ID 1n3w

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