As an approach to determine the structural basis of interactions between T cell receptors (TCRs) and MHC class I/peptide complexes, the fine specificities of a panel of vesicular stomatitis virus (VSV)-specific CTL clones recognizing the antigenic peptide (nucleoprotein 52-59) and the class I (Kb) molecule were correlated with the TCR primary structure. Each TCR showed a distinct interaction pattern with N52-59 and the Kb molecule. The large majority of the TCRs expressed by the panel of CTL clones used V beta 13 gene segments that had randomly recombined with D beta and J beta gene segments. The alpha chains were from randomly assorted V alpha and J alpha gene segments. Thus, the panel was found to be a highly heterogeneous set of TCRs, each member of which appeared to have an unique surface interface area, the recognition site, that interacted with a complementary surface formed by the single peptide bound in the class I antigenic groove.