Structural consequences of humanizing an antibody.

• DOI: 10.4049/jimmunol.158.5.2192
• Publication Date: 2022-12-31T13:32:09Z
• Authors: M A Holmes; J Foote
• Keywords: Complementarity (molecular biology); Molecular replacement

We have determined the crystal structure of Fv fragment a humanized anti-hen eggwhite lysozyme Ab (HuLys). This molecule is composite known structures: complementarity-determining regions (CDRs) were from mouse anti-lysozyme D1.3, heavy chain framework human myeloma protein NEW, and light consensus sequences similar to Bence Jones REI. HuLys crystallized in space group P4(3)2(1)2, with two molecules crystallographic asymmetric unit. The was solved by molecular replacement, using parent structures as search model. resolution 2.87 A, an R factor 22%. There several unanticipated structural similarities differences between structures. close or closer conformation D1.3 than NEW REI protein, despite overwhelming sequence identity regions. effect most pronounced at CDR-framework junction, showing that CDRs can induce changes residues, having net reconforming into more like D1.3. In combining site, grafted retained conformational equilibria seen demonstrating humanizing be applied Abs bind Ags through isomeric equilibrium induced fit mechanisms. addition, showed systematic resembled domain rotations reported for other Abs. However, V(H)-V(L) interface itself unaffected, apparent movement actually caused rearrangements distant this surface.