Tetratricopeptide repeat - TPR

TPR is a structural motif present in a wide range of proteins. It mediates protein-protein interactions and the assembly of multiprotein complexes. The TPR motif consists of 3-16 tandem-repeats of 34 amino acids residues, although individual TPR motifs can be dispersed in the protein sequence. Sequence alignment of the TPR domains reveals a consensus sequence defined by a pattern of small and large amino acids. TPR motifs have been identified in various different organisms, ranging from bacteria to humans. Proteins containing TPRs are involved in a variety of biological processes, such as cell cycle regulation, transcriptional control, mitochondrial and peroxisomal protein transport, neurogenesis and protein folding. The X-ray structure of a domain containing three TPRs from protein phosphatase 5 revealed that TPR adopts a helix-turn-helix arrangement, with adjacent TPR motifs packing in a parallel fashion, resulting in a spiral of repeating anti-parallel alpha-helices.