3okd

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=KDO:3-DEOXY-D-MANNO-OCT-2-ULOSONIC+ACID'>KDO</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3oke|3oke]], [[3okk|3okk]], [[3mhl|3mhl]], [[3mhm|3mhm]], [[3mhn|3mhn]], [[3mho|3mho]]</div></td></tr>

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== Publication Abstract from PubMed ==

The crystal structures of the antigen-binding fragment of the murine monoclonal antibody (mAb) S25-39 in the presence of several antigens representing chlamydial lipopolysaccharide (LPS) epitopes based on the bacterial sugar 3-deoxy-alpha-d-manno-oct-2-ulosonic acid (Kdo) have been determined at resolutions from 2.4 to 1.8 A. The antigen-binding site of this antibody differs from the well-characterized antibody S25-2 by a single mutation away from the germline of asparagine H53 to lysine, yet this one mutation results in a significant increase in avidity across a range of antigens. A comparison of the two antibody structures reveals that the mutated Lys H53 forms additional hydrogen bonds and/or charged-residue interactions with the second Kdo residue of every antigen having two or more carbohydrate residues. Significantly, the NH53K mutation results from a single nucleotide substitution in the germline sequence common among a panel of antibodies raised against glycoconjugates containing carbohydrate epitopes of chlamydial LPS. Like S25-2, S25-39 displays significant induced fit of complementarity determining region (CDR) H3 upon antigen binding, with the unliganded structure possessing a conformation distinct from those reported earlier for S25-2. The four different observed conformations for CDR H3 suggest that this CDR has evolved to exploit the recognition potential of a flexible loop while minimizing the associated entropic penalties of binding by adopting a limited number of ordered conformations in the unliganded state. These observations reveal strategies evolved to balance adaptability and specificity in the germline antibody response to carbohydrate antigens.

A Common NH53K Mutation in the Combining Site of Antibodies Raised against Chlamydial LPS Glycoconjugates Significantly Increases Avidity.,Blackler RJ, Muller-Loennies S, Brooks CL, Evans DW, Brade L, Kosma P, Brade H, Evans SV Biochemistry. 2011 Apr 1. PMID:21405106<ref>PMID:21405106</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 3okd" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Blackler, R J]]

[[Category: Evans, S V]]

[[Category: Immune system]]