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==Solution Structure of the Cd-loaded form of a Metallothionein from Helix Pomatia==
<StructureSection load='6qk6' size='340' side='right'caption='[[6qk6]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6qk6]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Helix_pomatia Helix pomatia]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6QK6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6QK6 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CD:CADMIUM+ION'>CD</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=6qk6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6qk6 OCA], [https://pdbe.org/6qk6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6qk6 RCSB], [https://www.ebi.ac.uk/pdbsum/6qk6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6qk6 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MTCD_HELPO MTCD_HELPO] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Metallothioneins (MTs) are cysteine-rich polypeptides that are naturally found coordinated to monovalent and/or divalent transition metal ions. Three metallothionein isoforms from the Roman snail Helix pomatia are known. They differ in their physiological metal load and in their specificity for transition metal ions such as Cd(2+) (HpCdMT isoform) and Cu(+) (HpCuMT isoform) or in the absence of a defined metal specificity (HpCd/CuMT isoform). We have determined the solution structure of the Cd-specific isoform (HpCdMT) by nuclear magnetic resonance spectroscopy using recombinant isotopically labeled protein loaded with Zn(2+) or Cd(2+). Both structures display two-domain architectures, where each domain comprises a characteristic three-metal cluster similar to that observed in the beta-domains of vertebrate MTs. The polypeptide backbone is well-structured over the entire sequence, including the interdomain linker. Interestingly, the two domains display mutual contacts, as observed before for the metallothionein of the snail Littorina littorea, to which both N- and C-terminal domains are highly similar. Increasing the length of the linker motionally decouples both domains and removes mutual contacts between them without having a strong effect on the stability of the individual domains. The structures of Cd6- and Zn6-HpCdMT are nearly identical. However, (15)N relaxation, in particular (15)N R2 rates, is accelerated for many residues of Zn6-HpCdMT but not for Cd6-HpCdMT, revealing the presence of conformational exchange effects. We suggest that this snail MT isoform is evolutionarily optimized for binding Cd rather than Zn.

The Solution Structure and Dynamics of Cd-Metallothionein from Helix pomatia Reveal Optimization for Binding Cd over Zn.,Beil A, Jurt S, Walser R, Schonhut T, Guntert P, Palacios O, Atrian S, Capdevila M, Dallinger R, Zerbe O Biochemistry. 2019 Nov 12;58(45):4570-4581. doi: 10.1021/acs.biochem.9b00830., Epub 2019 Oct 29. PMID:31633358<ref>PMID:31633358</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6qk6" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Helix pomatia]]
[[Category: Large Structures]]
[[Category: Beil A]]
[[Category: Jurt S]]
[[Category: Zerbe O]]