jm6b01509_si_003.pdb (147.52 kB)
Design of Potent and Selective Cathepsin G Inhibitors Based on the Sunflower Trypsin Inhibitor‑1 Scaffold
dataset
posted on 2017-01-03, 00:00 authored by Joakim E. Swedberg, Choi Yi Li, Simon J. de Veer, Conan K. Wang, David J. CraikNeutrophils
are directly responsible for destroying invading pathogens
via reactive oxygen species, antimicrobial peptides, and neutrophil
serine proteases (NSPs). Imbalance between NSP activity and endogenous
protease inhibitors is associated with chronic inflammatory disorders,
and engineered inhibitors of NSPs are a potential therapeutic pathway.
In this study we characterized the extended substrate specificity
(P4–P1) of the NSP cathepsin G using a peptide substrate library.
Substituting preferred cathepsin G substrate sequences into sunflower
trypsin inhibitor-1 (SFTI-1) produced a potent cathepsin G inhibitor
(Ki = 0.89 nM). Cathepsin G’s P2′
preference was determined by screening against a P2′ diverse
SFTI-based library, and the most preferred residue at P2′ was
combined in SFTI-1 with a preferred substrate sequence (P4–P2)
and a nonproteinogenic P1 residue (4-guanidyl-l-phenylalanine)
to produce a potent (Ki = 1.6 nM) and
the most selective (≥360-fold) engineered cathepsin G inhibitor
reported to date. This compound is a promising lead for further development
of cathepsin G inhibitors targeting chronic inflammatory disorders.