Determination of disulphide bridges in PG-2, an antimicrobial peptide from porcine leukocytes

✍ Scribed by Sylvia S. L. Harwig; Kristine M. Swiderek; Terry D. Lee; Robert I. Lehrer

• Book ID: 105360094
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 578 KB
• Volume: 1
• Category: Article
• ISSN: 1075-2617
• DOI: 10.1002/psc.310010308

✦ Synopsis

We determined the cysteine connectivity of protegrin PG-2, a leukocyte-derived antimicrobial peptide, by performing sequential enzyme digestions with chymotrypsin and thermolysin, and monitoring each digest by direct liquid chromatography-electrospray mass spectrometric analysis. This approach resolved the disulphide pairing pattern unambiguously with only picomolar amounts of PG-2. The inferred cysteine connectivity was confirmed by traditional amino acid composition analyses using nanomolar amounts of the protegrin. The results suggest that protegrins will assume a tachyplesin-like, disulphide-stabilized anti-parallel beta-sheet configuration in solution.