Publication Date:
1997-06-13
Description:
The crystal structures of a germline antibody Fab fragment and its complex with hapten have been solved at 2.1 A resolution. These structures are compared with the corresponding crystal structures of the affinity-matured antibody, 48G7, which has a 30,000 times higher affinity for hapten as a result of nine replacement somatic mutations. Significant changes in the configuration of the combining site occur upon binding of hapten to the germline antibody, whereas hapten binds to the mature antibody by a lock-and-key fit mechanism. The reorganization of the combining site that was nucleated by hapten binding is further optimized by somatic mutations that occur up to 15 from bound hapten. These results suggest that the binding potential of the primary antibody repertoire may be significantly expanded by the ability of germline antibodies to adopt more than one combining-site configuration, with both antigen binding and somatic mutation stabilizing the configuration with optimal hapten complementarity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wedemayer, G J -- Patten, P A -- Wang, L H -- Schultz, P G -- Stevens, R C -- R01 AI39089/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1997 Jun 13;276(5319):1665-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9180069" target="_blank"〉PubMed〈/a〉
Keywords:
Antibodies, Catalytic/*chemistry/genetics/immunology
;
Antibody Affinity
;
Antibody Diversity
;
Antigen-Antibody Complex
;
Antigen-Antibody Reactions
;
Binding Sites
;
*Binding Sites, Antibody
;
Crystallography, X-Ray
;
*Evolution, Molecular
;
Haptens/immunology
;
Hydrogen Bonding
;
Immunoglobulin Fab Fragments/*chemistry/genetics/immunology
;
Molecular Sequence Data
;
Mutation
;
Protein Conformation
;
Protein Structure, Secondary
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
