Structural reconstruction of protein ancestry

Romain Rouet, David B Langley, Peter Schofield, Mary Christie, Brendan Roome, Benjamin T. Porebski, Ashley M. Buckle, Ben E. Clifton, Colin J. Jackson, Daniela Stock, Daniel Christ

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Ancestral protein reconstruction allows the resurrection and characterization of ancient proteins based on computational analyses of sequences of modern-day proteins. Unfortunately, many protein families are highly divergent and not suitable for sequence-based reconstruction approaches. This limitation is exemplified by the antigen receptors of jawed vertebrates (B- and T-cell receptors), het-erodimers formed by pairs of Ig domains. These receptors are believed to have evolved from an extinct homodimeric ancestor through a process of gene duplication and diversification; however molecular evidence has so far remained elusive. Here, we use a structural approach and laboratory evolution to reconstruct such molecules and characterize their interaction with antigen. High-resolution crystal structures of reconstructed homodimeric receptors in complex with hen-egg white lysozyme demonstrate how nanomolar affinity binding of asymmetrical antigen is enabled through selective recruitment and structural plasticity within the receptor-binding site. Our results provide structural evidence in support of long-held theories concerning the evolution of antigen receptors, and provide a blueprint for the experimental reconstruction of protein ancestry in the absence of phylogenetic evidence.

Original languageEnglish
Pages (from-to)3897-3902
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number15
DOIs
Publication statusPublished - 11 Apr 2017

Keywords

  • Antibody
  • Directed evolution
  • Homodimer
  • Protein evolution
  • Protein structure

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