9Q0P

Human anti-EBV gH/gL Fab (AMMO1) with G111T light chain mutation

Summary for 9Q0P

• Entry DOI: 10.2210/pdb9q0p/pdb
• Descriptor: IgG heavy chain, IgG lambda light chain, GLYCEROL, ... (4 entities in total)
• Functional Keywords: ebv, antibody, fab, lambda, immune system
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 2
• Total formula weight: 47347.65

Authors

Young, T. (deposition date: 2025-08-13, release date: 2025-12-03)

Primary citation

Jewel, Y.,Young, T.,Park, M.,Ly, K.,Gonzalez, A.,Mallett, T.C.,Williams, J.C.
Single-residue engineering of lambda ( lambda ) antibody light chains reduces conformational flexibility and enhances thermal stability.
Comput Struct Biotechnol J, 27:4730-4739, 2025

PubMed Abstract: Monoclonal antibodies with lambda (λ) light chains are less commonly used in therapeutics due to their lower biophysical stability compared to kappa (κ) variants. Here, we identify a conserved glycine residue (Gly111) in the λ light chain hinge as a driver of large-scale Fab elbow-angle transitions. Using microsecond-scale molecular dynamics simulations of the EBV-neutralizing Fab AMMO1, we show that substituting Gly111 with threonine (G111T) increases the free energy barrier between conformational states, effectively arresting these transitions. Structural and biophysical analyses-including crystallography, differential scanning fluorimetry, and surface plasmon resonance-confirm that the mutation maintains Fab architecture and antigen binding while increasing thermal stability by up to 2.5 °C. The same mutation applied to a second λ-Fab yielded similar stabilization, and simulations of three clinical λ-Fabs revealed consistent reductions in elbow-angle flexibility. These results demonstrate a generalizable, single-residue engineering strategy to enhance the stability of λ-based Fabs without compromising function, with direct implications for therapeutic antibody development and manufacturability.

PubMed: 41245890
DOI: 10.1016/j.csbj.2025.10.045

Experimental method

X-RAY DIFFRACTION (2.08 Å)