High-throughput screening methodologies are already used in structural biology to define efficient protein crystallization and expression conditions. Meanwhile, screening approaches have been extended to the optimization of genetic constructs for improved soluble protein expression. With similarities to the directed evolution strategies used in protein engineering, a target gene encoding a poorly expressed protein is mutated by truncation, fragmentation or site-directed mutation.
In structural biology, both protein expression and crystallization processes contain large numbers of experimental variables that interact in complex ways and outcomes are often difficult or impossible to predict. In these situations, the desired result can be achieved by searching through a high diversity of possible solutions rather than by rational design.