The tetratricopeptide repeat: A structural motif mediating protein-protein interactions

The tetratricopeptide repeat (TPR) motif is a protein-protein interaction module\ud found in multiple copies in a number of functionally different proteins that facilitates\ud specific interactions with a partner protein(s). Three-dimensional structural\ud data have shown that a TPR motif contains two antiparallel a-helices such that\ud tandem arrays of TPR motifs generate a right-handed helical structure with an\ud amphipathic channel that might accommodate the complementary region of a\ud target protein. Most TPR-containing proteins are associated with multiprotein\ud complexes, and there is extensive evidence indicating that TPR motifs are\ud important to the functioning of chaperone, cell-cycle, transcription, and protein\ud transport complexes. The TPR motif may represent an ancient protein-protein\ud interaction module that has been recruited by different proteins and adapted for\ud specific functions