Structure based design of protein ligands: a study of antibody-like scaffolds targeted against the anthrax toxin.

Shiflett, P. ; Hong-Geller, E.

Technical Information Center Oak Ridge Tennessee

关键词: Affinity;    Antibodies;    Antigens;    Bacillus;    Chains;   

RP-ID  :  DE2001772829

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We have adopted structure-based approaches to enhance the affinities of two single chain antibodies, scFv1 and scFv4, that bind to two different epitopes on the Protective Antigen (PA), a toxin from Bacillus anthracis. In one approach, we have modified scFv4 and re-engineered a novel antibody-like scaffold in which we have placed V(sub L) on the N terminus and V(sub H) on the C-terminus and joined them by a 10 amino-acid-long linker. This scaffold preserves the native V(sub L)-V(sub H) contact interface and the dispositions of the CDR loops. It binds to PA with 10 fold higher affinity than scFv4. In a second approach, we have created a bispecific ligand by covalently joining scFv1 and scFv4 by a flexible linker that supports simultaneous and synergistic binding of the two scFvs to PA. This bispecific scFv1-linker-scFv4 binds to PA with 10 fold higher affinity than the individual scFvs. The newly re-engineered antibody-like scaffold of scFv4 and scFv1-linker-scFv4 are expected to be potent inhibitors of PA binding to the host cells.