biostudies-literatureQuintero DNIGMS NIH HHS2079-2094https://www.ebi.ac.uk/biostudies/studies/S-EPMC6883771biostudies-literatureUnknown28(12)Sunflower trypsin inhibitor (SFTI) is a 14-amino-acid bicyclic peptide that contains a single internal disulfide bond. We initially constructed chimeras of SFTI with N-terminal secretion signals from the <i>Escherichia coli</i> OmpA and <i>Pseudomonas aeruginosa</i> ToxA, but only detected small amounts of protease inhibition resulting from these constructs. A substantially higher degree of protease inhibition was detected from a C-terminal SFTI fusion with <i>E. coli</i> YebF, which radiated more than a centimeter from an individual colony of <i>E. coli</i> using a culture-based inhibitor assay. Inhibitory activity was further improved in YebF-SFTI fusions by the addition of a trypsin cleavage signal immediately upstream of SFTI, and resulted in production of a 14-amino-acid, disulfide-boJournal of microbiology and biotechnologyCo-Expression of a Chimeric Protease Inhibitor Secreted by a Tumor-Targeted <i>Salmonella</i> Protects Therapeutic Proteins from Proteolytic Degradation.PMC6883771SC3 GM098207R25 GM063787Vincent LQuintero DCarrafa JWohlschlegel JLee HJBermudes DfalseCo-Expression of a Chimeric Protease Inhibitor Secreted by a Tumor-Targeted <i>Salmonella</i> Protects Therapeutic Proteins from Proteolytic Degradation.Sunflower trypsin inhibitor (SFTI) is a 14-amino-acid bicyclic peptide that contains a single internal disulfide bond. We initially constructed chimeras of SFTI with N-terminal secretion signals from the <i>Escherichia coli</i> OmpA and <i>Pseudomonas aeruginosa</i> ToxA, but only detected small amounts of protease inhibition resulting from these constructs. A substantially higher degree of protease inhibition was detected from a C-terminal SFTI fusion with <i>E. coli</i> YebF, which radiated more than a centimeter from an individual colony of <i>E. coli</i> using a culture-based inhibitor assay. Inhibitory activity was further improved in YebF-SFTI fusions by the addition of a trypsin cleavage signal immediately upstream of SFTI, and resulted in production of a 14-amino-acid, disulfide-bo2018-01-01T00:00:00Z2018 Dec2026-05-03T14:48:21.199Z2020-10-29T12:19:41ZS-EPMC68837713066134610.4014/jmb.1807.0803610.4014/jmb.1808.08036