α1-Antitrypsin Portland, a bioengineered serpin highly selective for furin: Application as an antipathogenic agent

François Jean, Kori Stella, Laurel Thomas, Gseping Liu, Yang Kevin Xiang, Andrew J. Reason, Gary Thomas

Research output: Contribution to journalArticle

223 Scopus citations

Abstract

The important role of furin in the proteolytic activation of many pathogenic molecules has made this endoprotease a target for the development of potent and selective antiproteolytic agents. Here, we demonstrate the utility of the protein-based inhibitor α1-antitrypsin Portland (α1-PDX) as an antipathogenic agent that can be used prophylactically to block furin- dependent cell killing by Pseudomonas exotoxin A. Biochemical analysis of the specificity of a bacterially expressed Hisand FLAG-tagged α1-PDX (α1- PDX/hf) revealed the selectivity of the α1-PDX/hf reactive site loop for furin (K(i), 600 pM) but not for other proprotein convertase family members or other unrelated endoproteases. Kinetic studies show that α1-PDX/hf inhibits furin by a slow tight-binding mechanism characteristic of serpin molecules and functions as a suicide substrate inhibitor. Once bound to furin's active site, α1-PDX/hf partitions with equal probability to undergo proteolysis by furin at the C-terminal side of the reactive center - Arg355-Ile-Pro-Arg358-↓ or to form a kinetically trapped SDS-stable complex with the enzyme. This partitioning between the complex-forming and proteolytic pathways contributes to the ability of α1-PDX/hf to differentially inhibit members of the proprotein convertase family. Finally, we propose a structural model of the α1-PDX-reactive site loop that explains the high degree of enzyme selectivity of this serpin and which can be used to generate small molecule furin inhibitors.

Original languageEnglish (US)
Pages (from-to)7293-7298
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume95
Issue number13
DOIs
StatePublished - Jun 23 1998
Externally publishedYes

ASJC Scopus subject areas

  • General
  • Genetics

Fingerprint Dive into the research topics of 'α<sub>1</sub>-Antitrypsin Portland, a bioengineered serpin highly selective for furin: Application as an antipathogenic agent'. Together they form a unique fingerprint.

  • Cite this