Designing repeat proteins: a modular approach to protein design.

Repeat proteins present unique opportunities for engineering because of their modular nature that potentially allows LEGO® like construction of macromolecules. Nature takes advantage of these properties and uses this type of scaffold for recognition, structure, and even signaling purposes. In recent years, new protein modeling tools facilitated the design of novel repeat proteins, creating possibilities beyond naturally occurring scaffolds alone. We highlight here the different design strategies and summarize the various structural families and novel proteins achieved.