6SS6

Structure of arginase-2 in complex with the inhibitory human antigen-binding fragment Fab C0020187

This is a non-PDB format compatible entry.

Summary for 6SS6

• Entry DOI: 10.2210/pdb6ss6/pdb
• Related: 6SRV 6SRX 6SS0 6SS2 6SS4 6SS5 6TUL
• Descriptor: Arginase-2, mitochondrial, Fab C0020187 heavy chain (IgG1), Fab C0020187 light chain (IgG1), ... (5 entities in total)
• Functional Keywords: arginase-2 inhibitor, igg, antigen-binding fragment, protein binding
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 9
• Total formula weight: 258980.88

Authors

Burschowsky, D.,Addyman, A.,Fiedler, S.,Groves, M.,Haynes, S.,Seewooruthun, C.,Carr, M. (deposition date: 2019-09-06, release date: 2020-06-10, Last modification date: 2024-10-23)

Primary citation

Chan, D.T.Y.,Jenkinson, L.,Haynes, S.W.,Austin, M.,Diamandakis, A.,Burschowsky, D.,Seewooruthun, C.,Addyman, A.,Fiedler, S.,Ryman, S.,Whitehouse, J.,Slater, L.H.,Gowans, E.,Shibata, Y.,Barnard, M.,Wilkinson, R.W.,Vaughan, T.J.,Holt, S.V.,Cerundolo, V.,Carr, M.D.,Groves, M.A.T.
Extensive sequence and structural evolution of Arginase 2 inhibitory antibodies enabled by an unbiased approach to affinity maturation.
Proc.Natl.Acad.Sci.USA, 117:16949-16960, 2020

PubMed Abstract: Affinity maturation is a powerful technique in antibody engineering for the in vitro evolution of antigen binding interactions. Key to the success of this process is the expansion of sequence and combinatorial diversity to increase the structural repertoire from which superior binding variants may be selected. However, conventional strategies are often restrictive and only focus on small regions of the antibody at a time. In this study, we used a method that combined antibody chain shuffling and a staggered-extension process to produce unbiased libraries, which recombined beneficial mutations from all six complementarity-determining regions (CDRs) in the affinity maturation of an inhibitory antibody to Arginase 2 (ARG2). We made use of the vast display capacity of ribosome display to accommodate the sequence space required for the diverse library builds. Further diversity was introduced through pool maturation to optimize seven leads of interest simultaneously. This resulted in antibodies with substantial improvements in binding properties and inhibition potency. The extensive sequence changes resulting from this approach were translated into striking structural changes for parent and affinity-matured antibodies bound to ARG2, with a large reorientation of the binding paratope facilitating increases in contact surface and shape complementarity to the antigen. The considerable gains in therapeutic properties seen from extensive sequence and structural evolution of the parent ARG2 inhibitory antibody clearly illustrate the advantages of the unbiased approach developed, which was key to the identification of high-affinity antibodies with the desired inhibitory potency and specificity.

PubMed: 32616569
DOI: 10.1073/pnas.1919565117

Experimental method

X-RAY DIFFRACTION (3.25 Å)