2a6i

Publication Abstract from PubMed

Correlation between the promiscuity of the primary antibody response and conformational flexibility in a germline antibody was addressed by using germline antibody 36-65. Crystallographic analyses of the 36-65 Fab with three independent dodecapeptides provided mechanistic insights into the generation of antibody diversity. While four antigen-free Fab molecules provided a quantitative description of the conformational repertoire of the antibody CDRs, three Fab molecules bound to structurally diverse peptide epitopes exhibited a common paratope conformation. Each peptide revealed spatially different footprints within the antigen-combining site. However, a conformation-specific lock involving two shared residues, which were also associated with hapten binding, was discernible. Unlike the hapten, the peptides interacted with residues that undergo somatic mutations, suggesting a possible mechanism for excluding "nonspecific" antigens during affinity maturation. The observed multiple binding modes of diverse epitopes within a common paratope conformation of a germline antibody reveal a simple, yet elegant, mechanism for expanding the primary antibody repertoire.

Differential epitope positioning within the germline antibody paratope enhances promiscuity in the primary immune response.,Sethi DK, Agarwal A, Manivel V, Rao KV, Salunke DM Immunity. 2006 Apr;24(4):429-38. PMID:16618601^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.