View source for 1zkb


==Zinc-free Engineered maltose binding protein==
<StructureSection load='1zkb' size='340' side='right'caption='[[1zkb]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1zkb]] 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=1ZKB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1ZKB 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]] 2.2&#8491;</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=1zkb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1zkb OCA], [https://pdbe.org/1zkb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1zkb RCSB], [https://www.ebi.ac.uk/pdbsum/1zkb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1zkb ProSAT]</span></td></tr>
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== Function ==
[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.
== 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/zk/1zkb_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1zkb ConSurf].
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== Publication Abstract from PubMed ==
Protein engineering was used previously to convert maltose-binding protein (MBP) into a zinc biosensor. Zn(2+) binding by the engineered MBP was thought to require a large conformational change from "open" to "closed", similar to that observed when maltose is bound by the wild-type protein. We show that although this re-designed MBP molecule binds Zn(2+) with high affinity as previously reported, it does not adopt a closed conformation in solution as assessed by small-angle X-ray scattering. High-resolution crystallographic studies of the engineered Zn(2+)-binding MBP molecule demonstrate that Zn(2+) is coordinated by residues on the N-terminal lobe only, and therefore Zn(2+) binding does not require the protein to adopt a fully closed conformation. Additional crystallographic studies indicate that this unexpected Zn(2+) binding site can also coordinate Cu(2+) and Ni(2+) with only subtle changes in the overall conformation of the protein. This work illustrates that the energetic barrier to domain closure, which normally functions to maintain MBP in an open concentration in the absence of ligand, is not easily overcome by protein design. A comparison to the mechanism of maltose-induced domain rearrangement is discussed.

Structural studies of an engineered zinc biosensor reveal an unanticipated mode of zinc binding.,Telmer PG, Shilton BH J Mol Biol. 2005 Dec 9;354(4):829-40. Epub 2005 Oct 28. PMID:16288781<ref>PMID:16288781</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Maltose-binding protein 3D structures|Maltose-binding protein 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Shilton BH]]
[[Category: Telmer PG]]