TPR proteins: the versatile helix.

Tetratrico peptide repeat (TPR) proteins have several interesting properties, including their folding characteristics, modular architecture, and range of binding specificities. In the past 5 yr, many 3-dimensional structures of TPR domains have been solved, revealing at a mol. level the versatility of this basic fold. Here, the authors discuss the structure of TPRs and highlight the diversity of arrangements and functions that are assocd. with these ubiquitous domains. Genomic analyses of the distribution of TPR domains are presented along with implications for protein engineering.