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|3l5x, resolution 1.90Å ()|
|Gene:||IL13, NC30 (Homo sapiens)|
Crystal structure of the complex between IL-13 and H2L6 FAB
Humanization of a potent neutralizing mouse anti-human IL-13 antibody (m836) using a method called human framework adaptation (HFA) is reported. HFA consists of two steps: human framework selection (HFS) and specificity-determining residue optimization (SDRO). The HFS step involved generation of a library of m836 antigen binding sites combined with diverse human germline framework regions (FRs), which were selected based on structural and sequence similarities between mouse variable domains and a repertoire of human antibody germline genes. SDRO consisted of diversifying specificity-determining residues and selecting variants with improved affinity using phage display. HFS of m836 resulted in a 5-fold loss of affinity, whereas SDRO increased the affinity up to 100-fold compared to the HFS antibody. Crystal structures of Fabs in complex with IL-13 were obtained for m836, the HFS variant chosen for SDRO, and one of the highest-affinity SDRO variants. Analysis of the structures revealed that major conformational changes in FR-H1 and FR-H3 occurred after FR replacement, but none of them had an evident direct impact on residues in contact with IL-13. Instead, subtle changes affected the V(L)/V(H) (variable-light domain/variable-heavy domain) interface and were likely responsible for the 5-fold decreased affinity. After SDRO, increased affinity resulted mainly from rearrangements in hydrogen-bonding pattern at the antibody/antigen interface. Comparison with m836 putative germline genes suggested interesting analogies between natural affinity maturation and the engineering process that led to the potent HFA anti-human IL-13 antibody.
Human framework adaptation of a mouse anti-human IL-13 antibody., Fransson J, Teplyakov A, Raghunathan G, Chi E, Cordier W, Dinh T, Feng Y, Giles-Komar J, Gilliland G, Lollo B, Malia TJ, Nishioka W, Obmolova G, Zhao S, Zhao Y, Swanson RV, Almagro JC, J Mol Biol. 2010 Apr 30;398(2):214-31. Epub 2010 Mar 10. PMID:20226193
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[IL13_HUMAN] Defects in IL13 may be a cause of susceptibility to allergic rhinitis (ALRH) [MIM:607154]. Allergic rhinitis is a common disease of complex inheritance and is characterized by mucosal inflammation caused by allergen exposure.
[IL13_HUMAN] Cytokine. Inhibits inflammatory cytokine production. Synergizes with IL2 in regulating interferon-gamma synthesis. May be critical in regulating inflammatory and immune responses.
About this Structure
- Fransson J, Teplyakov A, Raghunathan G, Chi E, Cordier W, Dinh T, Feng Y, Giles-Komar J, Gilliland G, Lollo B, Malia TJ, Nishioka W, Obmolova G, Zhao S, Zhao Y, Swanson RV, Almagro JC. Human framework adaptation of a mouse anti-human IL-13 antibody. J Mol Biol. 2010 Apr 30;398(2):214-31. Epub 2010 Mar 10. PMID:20226193 doi:10.1016/j.jmb.2010.03.004