Cicular dichroism of hapten-antibody complexes: Calculation of the interaction of a trinitrophenyl hapten with tryptophan

Conformational flexibility of an antibody combining site composed of two identical V regions

“…For example, a change from a parallel orientation to a titled orientation may abolish the possibility for charge transfer. Nevertheless, the induced CD spectrum at pH 5.0 indicates that the Dnp is still interacting with a tryptophan residue [22] although in a slightly different orientation than that at pH 8.0, as indicated by the differences in the CD spectra at these two pH values (Fig. 6).…”

Role of tyrosines in the combining site of the dinitrophenyl-binding IgA myeloma M315: specific nitration and high-resolution proton nuclear magnetic resonance studies

“…The evidence suggesting that the Dnp ring interacts with a tryptophan side chain has been presented previously . This includes induced circular dichroism spectra of Dnp and Tnp ligands on binding to M315 (Freed et al, 1976;Orin et al, 1976) and the red shift in the ultraviolet absorption spectrum of the bound ligands. The more recent binding studies on Fv fragment in which all the tryphophans are deuterated (Gettins & Dwek, 1981) provide further strong evidence for the involvement of tryptophan with the Dnp.…”

Magnetic resonance studies of the binding site interactions between 19F-labeled nitrophenyl haptens and specific mouse myeloma immunoglobulin MOPC-315

“…The likely importance of such ring current contributions to the observed chemical shift finds support in the observation that nitrophenyldiazonium affinity labels react specifically with tyrosine-34 of the light chain of MOPC-315; this amino acid is in the first hypervariable region (Goetzl and Metzger, 1970b). Further evidence comes from circular dichroism studies of the binding of e-A'-2,4,6-trinitrophenylaminocaproate of MOPC-315; the circular dichroism spectrum of the complex showed strong interactions between this hapten and a nearby tryptophan residue(s) of the antibody (Freed et al, 1976;Orín et al, 1976). They calculated that an interaction of the hapten with only one tryptophan residue (with parallel or tilted orientations) would require a separation of 3.5 Á. Interaction with four tryptophans increased their calculated distance to 7 Á.…”