The tetratricopeptide repeat: a structural motif mediating protein-proteininteractions

The tetratricopeptide repeat (TPR) motif is a protein-protein interaction m odule found in multiple copies in a number of functionally different protei ns that facilitates specific interactions with a partner protein(s), Three- dimensional structural data have shown that a TPR motif contains two antipa rallel alpha-helices such that tandem arrays of TPR motifs generate a right -handed helical structure with an amphipathic channel that might accommodat e the complementary region of a target protein. Most TPR-containing protein s are associated with multiprotein complexes, and there is extensive eviden ce indicating that TPR motifs are important to the functioning of chaperone , cell-cycle, transcription, and protein transport complexes. The TPR motif may represent an ancient protein-protein interaction module that has been recruited by different proteins and adapted for specific functions. BioEssa ys 1999;21:932-939. (C) 1999 John Wiley & Sons, Inc.