5C7X

Crystal structure of MOR04357, a neutralizing anti-human GM-CSF antibody Fab fragment in complex with human GM-CSF

Summary for 5C7X

• Entry DOI: 10.2210/pdb5c7x/pdb
• Descriptor: Granulocyte-macrophage colony-stimulating factor, Immunglobulin G1 Fab fragment, heavy chain, Immunglobulin G1 Fab fragment, light chain, ... (7 entities in total)
• Functional Keywords: gm-csf, affinity maturation, phage display, cytokine, antibody, proteros biostructures gmbh, immune system
• Biological source: Homo sapiens (Human); More
• Cellular location: Secreted: P04141
• Total number of polymer chains: 6
• Total formula weight: 125246.02

Authors

Eylenstein, R.,Weinfurtner, D.,Steidl, S.,Boettcher, J.,Augustin, M. (deposition date: 2015-06-25, release date: 2015-10-14, Last modification date: 2024-11-20)

Primary citation

Eylenstein, R.,Weinfurtner, D.,Hartle, S.,Strohner, R.,Bottcher, J.,Augustin, M.,Ostendorp, R.,Steidl, S.
Molecular basis of in vitro affinity maturation and functional evolution of a neutralizing anti-human GM-CSF antibody.
Mabs, 8:176-186, 2016

PubMed Abstract: X-ray structure analysis of 4 antibody Fab fragments, each in complex with human granulocyte macrophage colony stimulating factor (GM-CSF), was performed to investigate the changes at the protein-protein binding interface during the course of in vitro affinity maturation by phage display selection. The parental antibody MOR03929 was compared to its derivatives MOR04252 (CDR-H2 optimized), MOR04302 (CDR-L3 optimized) and MOR04357 (CDR-H2 and CDR-L3 optimized). All antibodies bind to a conformational epitope that can be divided into 3 sub-epitopes. Specifically, MOR04357 binds to a region close to the GM-CSF N-terminus (residues 11-24), a short second sub-epitope (residues 83-89) and a third at the C-terminus (residues 112-123). Modifications introduced during affinity maturation in CDR-H2 and CDR-L3 led to the establishment of additional hydrogen bonds and van der Waals contacts, respectively, providing a rationale for the observed improvement in binding affinity and neutralization potency. Once GM-CSF is complexed to the antibodies, modeling predicts a sterical clash with GM-CSF binding to GM-CSF receptor α and β chain. This predicted mutually exclusive binding was confirmed by a GM-CSF receptor α chain ligand binding inhibition assay. Finally, high throughput sequencing of clones obtained after affinity maturation phage display pannings revealed highly selected consensus sequences for CDR-H2 as well for CDR-L3, which are in accordance with the sequence of the highest affinity antibody MOR04357. The resolved crystal structures highlight the criticality of these strongly selected residues for high affinity interaction with GM-CSF.

PubMed: 26406987
DOI: 10.1080/19420862.2015.1099774

Experimental method

X-RAY DIFFRACTION (2.95 Å)