Three-dimensional structures of idiotypically related Fabs with intermediate and high affinity for fluorescein.

Multi-disciplinary studies of fluorescein-protein conjugates have led to the generation of a family of antibodies with common idiotypes and affinities for fluorescein ranging over five orders of magnitude. The high affinity 4-4-20 prototype traps the ligand in a highly complementary binding slot, which is lined by multiple aromatic side-chains. An antibody (9-40) of intermediate affinity belongs to the same idiotypic family as 4-4-20 and shares substantial amino acid identities within the VL and VH domains.

Discrete bathochromic shifts exhibited by fluorescein ligand bound to rabbit polyclonal anti-fluorescein Fab fragments.

Eleven individual hyperimmune rabbit polyclonal anti-fluorescein Fab fragment preparations were resolved into heterogeneous subfractions based on differential dissociation times from a specific adsorbent. Four Fab subfractions (i.e.