3qxt: Difference between revisions
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==Structure of an Anti-Methotrexate CDR1-3 Graft VHH Antibody in Complex with Methotrexate== | |||
<StructureSection load='3qxt' size='340' side='right' caption='[[3qxt]], [[Resolution|resolution]] 1.70Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3qxt]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Lama_glama Lama glama]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QXT OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3QXT FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MTX:METHOTREXATE'>MTX</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1i3u|1i3u]], [[2x6m|2x6m]], [[3qxu|3qxu]], [[3qxv|3qxv]], [[3qxw|3qxw]]</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=3qxt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qxt OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3qxt RCSB], [http://www.ebi.ac.uk/pdbsum/3qxt PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Conventional anti-hapten antibodies typically bind low-molecular weight compounds (haptens) in the crevice between the variable heavy and light chains. Conversely, heavy chain-only camelid antibodies, which lack a light chain, must rely entirely on a single variable domain to recognize haptens. While several anti-hapten VHHs have been generated, little is known regarding the underlying structural and thermodynamic basis for hapten recognition. Here, an anti-methotrexate VHH (anti-MTX VHH) was generated using grafting methods whereby the three complementarity determining regions (CDRs) were inserted onto an existing VHH framework. Thermodynamic analysis of the anti-MTX VHH CDR1-3 Graft revealed a micromolar binding affinity, while the crystal structure of the complex revealed a somewhat surprising noncanonical binding site which involved MTX tunneling under the CDR1 loop. Due to the close proximity of MTX to CDR4, a nonhypervariable loop, the CDR4 loop sequence was subsequently introduced into the CDR1-3 graft, which resulted in a dramatic 1000-fold increase in the binding affinity. Crystal structure analysis of both the free and complex anti-MTX CDR1-4 graft revealed CDR4 plays a significant role in both intermolecular contacts and binding site conformation that appear to contribute toward high affinity binding. Additionally, the anti-MTX VHH possessed relatively high specificity for MTX over closely related compounds aminopterin and folate, demonstrating that VHH domains are capable of binding low-molecular weight ligands with high affinity and specificity, despite their reduced interface. | |||
An anti-hapten camelid antibody reveals a cryptic binding site with significant energetic contributions from a nonhypervariable loop.,Fanning SW, Horn JR Protein Sci. 2011 Jul;20(7):1196-207. doi: 10.1002/pro.648. Epub 2011 May, 23. PMID:21557375<ref>PMID:21557375</ref> | |||
== | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Lama glama]] | [[Category: Lama glama]] | ||
[[Category: Fanning, S W | [[Category: Fanning, S W]] | ||
[[Category: Horn, J R | [[Category: Horn, J R]] | ||
[[Category: Anti-hapten antibody]] | [[Category: Anti-hapten antibody]] | ||
[[Category: Antibody]] | [[Category: Antibody]] | ||