Open AccessExploring the cross‐reactivity of S25‐2: complex with a 5,6‐dehydro‐Kdo disaccharide
Author(s) -
Brooks Cory L.,
Wimmer Kurt,
Kosma Paul,
MüllerLoennies Sven,
Brade Lore,
Brade Helmut,
Evans Stephen V.
Publication year - 2013
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309112047422
Subject(s) - disaccharide , chemistry , stereochemistry , residue (chemistry) , ligand (biochemistry) , biochemistry , receptor
The near‐germline antibody S25‐2 exhibits a remarkable cross‐reactivity for oligosaccharides containing the bacterial lipopolysaccharide carbohydrate 3‐deoxy‐D‐ manno ‐oct‐2‐ulosonic acid (Kdo). The recent synthesis of a variety of Kdo analogues permits a detailed structural analysis of the importance of specific interactions in antigen recognition by S25‐2. The Kdo disaccharide analogue Kdo‐(2→4)‐5,6‐dehydro‐Kdo lacks a 5‐OH group on the second Kdo residue and has been cocrystallized with S25‐2. The structure reveals that the modification of the Kdo residue at position 5 results in a rearrangement of intramolecular hydrogen bonds in the antigen that allows it to assume a novel conformation in the antibody‐combining site. The cross‐reactive binding of S25‐2 to this synthetic ligand highlights the adaptability of this antibody to non‐natural synthetic analogues.