View source for 5esq


==Cetuximab Fab in complex with cyclic beta-alanine-linked meditope==
<StructureSection load='5esq' size='340' side='right'caption='[[5esq]], [[Resolution|resolution]] 2.55&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5esq]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ESQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5ESQ 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]] 2.55&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BAL:BETA-ALANINE'>BAL</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=5esq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5esq OCA], [https://pdbe.org/5esq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5esq RCSB], [https://www.ebi.ac.uk/pdbsum/5esq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5esq ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Recently, a unique binding site for a cyclic 12-residue peptide was discovered within a cavity formed by the light and heavy chains of the cetuximab Fab domain. In order to better understand the interactions that drive this unique complex, a number of variants including the residues within the meditope peptide and the antibody, as well as the cyclization region of the meditope peptide, were created. Here, multiple crystal structures of meditope peptides incorporating different cyclization strategies bound to the central cavity of the cetuximab Fab domain are presented. The affinity of each cyclic derivative for the Fab was determined by surface plasmon resonance and correlated to structural differences. Overall, it was observed that the disulfide bond used to cyclize the peptide favorably packs against a hydrophobic `pocket' and that amidation and acetylation of the original disulfide meditope increased the overall affinity approximately 2.3-fold. Conversely, replacing the terminal cysteines with serines and thus creating a linear peptide reduced the affinity over 50-fold, with much of this difference being reflected in a decrease in the on-rate. Other cyclization methods, including the formation of a lactam, reduced the affinity but not to the extent of the linear peptide. Collectively, the structural and kinetic data presented here indicate that small perturbations introduced by different cyclization strategies can significantly affect the affinity of the meditope-Fab complex.

Cyclization strategies of meditopes: affinity and diffraction studies of meditope-Fab complexes.,Bzymek KP, Ma Y, Avery KA, Horne DA, Williams JC Acta Crystallogr F Struct Biol Commun. 2016 Jun;72(Pt 6):434-42. doi:, 10.1107/S2053230X16007202. Epub 2016 May 23. PMID:27303895<ref>PMID:27303895</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5esq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Virus protease 3D structures|Virus protease 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Synthetic construct]]
[[Category: Bzymek KP]]
[[Category: Williams JC]]