Expression of Soluble Proteins by Random Incremental Truncation (ESPRIT) is a directed evolution-type process combining random deletion mutagenesis with high throughput solubility screening.
ESPRIT uses exonuclease to truncate the target gene sequence and generate all possible construct termini. Up to 28,000 clones are isolated using colony picking robots and gridded out to form high density colony arrays for protein expression testing. This means ESPRIT is able to screen of tens of thousands of constructs of a single gene to identify well-behaving soluble constructs.
When the full-length protein cannot be expressed and a domain-focused approach is necessary, it can be difficult to design well-expressing soluble constructs. Common issues are:
ESPRIT technology was developed to express proteins whose domain boundaries are difficult to predict.
Over the last ten years, the ESPRIT platform has been visited by many European scientists who have brought their problematic targets for screening. About half of these users have returned home with soluble, purified proteins for further study.
Leupold S, et al., (2017) Structural insights into the architecture of the Shigella flexneri virulence factor IcsA/VirG and motifs involved in polar distribution and secretion. J Struct Biol. 2017 Apr;198(1):19-27
Yerabham ASK, et al., (2017) A structural organization for the Disrupted in Schizophrenia 1 protein, identified by high-throughput screening, reveals distinctly folded regions, which are bisected by mental illness-related mutations. J Biol Chem. 2017 Apr 21;292(16):6468-6477
Rawlings AE, et al., (2010) Expression of soluble, active fragments of the morphogenetic protein SpoIIE from Bacillus subtilis using a library-based construct screen. Protein Eng Des Sel. 2010 Nov;23(11):817-25
For information, see the ISBG webpage.