The Design of Repeat Proteins: Stability Conflicts with Functionality

Abstract

Repeat proteins are constituted by a variable number of copies of a given structural element that is tandemly repeated along a longitudinal axis. They mainly function as protein-protein interactors with binding interfaces that are not conserved along members of the same family but specific for each interacting pair. These proteins have been extensively used as scaffolds for protein design that are usually centered on the maximization of the stability of the repeat arrays. Although overall stability is important for obtaining molecules with enhanced solubility and expression, natural occurring repeatproteins have unstable characteristics that are relevant for their binding properties. Here we discuss the state of the art for repeat protein designs and the ideas of allowing energetic conflicts for introducing enhanced functionality in the arrays.