Systematic analysis of CDR contacts and sequence constraints between T cell receptor <i>αβ</i> chains

Motivation: The six complementarity determining regions (CDRs) of the T cell receptor (TCR) form multiple contacts with cognate peptide and major histocompatibility complex, thus determining antigen specificity. However, the contacts between the CDRs themselves are less understood.

Results: Our systematic study of all available TCR crystallographic structures identified consistent patterns of intra- and inter-chain CDR contacts in both free and antigen-bound TCRs. In addition, the protein sequences of TCRα and TCRβ from sets of TCRs which recognise a shared antigen shared mutual information and were not independent. As a result, sequence-based models can partially predict TCRα/TCRβ pairing de novo. The conserved patterns of CDR amino acid contacts, and the mutual sequence constraints between antigen-specific sets of TCR α and β chains represent an under-appreciated element of TCR structure, which may play an important role in T cell antigen recognition.

Availability and Implementation: The code and data necessary to reproduce the analyses are available at https://github.com/mm523/TCRab-pairing.

Supplementary Information: Supplementary data are available at Bioinformatics online.