Role of κ→λ light-chain constant-domain switch in the structure and functionality of A17 reactibody

• Published in: Acta crystallographica. Section D, Biological crystallography. Vol. 70; no. 3; pp. 708 - 719
• Main Authors: Ponomarenko, Natalia, Chatziefthimiou, Spyros D., Kurkova, Inna, Mokrushina, Yuliana, Stepanova, Anastasiya, Smirnov, Ivan, Avakyan, Marat, Bobik, Tatyana, Mamedov, Azad, Mitkevich, Vladimir, Belogurov Jr, Alexey, Fedorova, Olga S., Dubina, Michael, Golovin, Andrey, Lamzin, Victor, Friboulet, Alain, Makarov, Alexander A., Wilmanns, Matthias, Gabibov, Alexander
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.03.2014
• Subjects: A17 reactibody; AFFINITY; ANTIBODIES; ATOMS; Complementarity Determining Regions - chemistry; Complementarity Determining Regions - genetics; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL STRUCTURE; Crystallization; Crystallography, X-Ray; CRYSTALS; DESIGN; DOMAIN STRUCTURE; EFFICIENCY; Humans; Immunoglobulin Constant Regions - chemistry; Immunoglobulin Constant Regions - genetics; Immunoglobulin Heavy Chains - chemistry; Immunoglobulin Heavy Chains - genetics; Immunoglobulin kappa-Chains - chemistry; Immunoglobulin kappa-Chains - genetics; Immunoglobulin lambda-Chains - chemistry; Immunoglobulin lambda-Chains - genetics; Immunoglobulin Switch Region - genetics; INTERACTIONS; LIGANDS; MOBILITY; Recombinant Proteins - chemistry; Research Papers; RESOLUTION; SUBSTRATES; Thermodynamics; VISIBLE RADIATION; A17 reactibody; antibodies
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S1399004713032446

The engineering of catalytic function in antibodies requires precise information on their structure. Here, results are presented that show how the antibody domain structure affects its functionality. The previously designed organophosphate‐metabolizing reactibody A17 has been re‐engineered by replacing its constant κ light chain by the λ chain (A17λ), and the X‐ray structure of A17λ has been determined at 1.95 Å resolution. It was found that compared with A17κ the active centre of A17λ is displaced, stabilized and made more rigid owing to interdomain interactions involving the CDR loops from the VL and VH domains. These VL/VH domains also have lower mobility, as deduced from the atomic displacement parameters of the crystal structure. The antibody elbow angle is decreased to 126° compared with 138° in A17κ. These structural differences account for the subtle changes in catalytic efficiency and thermodynamic parameters determined with two organophosphate ligands, as well as in the affinity for peptide substrates selected from a combinatorial cyclic peptide library, between the A17κ and A17λ variants. The data presented will be of interest and relevance to researchers dealing with the design of antibodies with tailor‐made functions.