Minimization of a eukaryotic mini-intein

Inteins are internal protein splicing elements that can autocatalytically self-excise from their host protein and ligate the protein flanks (exteins) with a peptide bond. Large inteins comprise independent protein splicing and endonuclease domains whereas mini-inteins lack the central endonuclease domain. To identify mini-intein domains that are essential for protein splicing, deletions were introduced at different sites of the 157-aa PRPS mini-intein of Penicillium chrysogenum. The removal of eight and six amino acids at two different sites resulted in a functional eukaryotic mini-intein of only 143 aa. (c) 2007 Elsevier Inc. All rights reserved.