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Title: The elastase-PK101 structure: Mechanism of an ultrasensitive activity-based probe revealed

Human neutrophil elastase (HNE) plays a central role in neutrophil host defense, but its broad specificity makes HNE a difficult target for both inhibitor and probe development. Recently, we identified the unnatural amino acid containing activity-based probe PK101, which exhibits astounding sensitivity and selectivity for HNE, yet completely lacks mechanistic explanation for its unique characteristics. Here, we present the crystal structure of the HNE-PK101 complex which not only reveals the basis for PK101 ultrasensitivity but also uncovers so far unrecognized HNE features. Strikingly, the Nle(O-Bzl) function in the P4 position of PK101 reveals and leverages an “exo-pocket” on HNE as a critical factor for selectivity. Furthermore, the PK101 P3 position harbors a methionine dioxide function, which mimics a post-translationally oxidized methionine residue and forms a critical hydrogen bond to the backbone amide of Gly219 of HNE. Gly219 resides in a Gly–Gly motif that is unique to HNE, yet compulsory for this interaction. Consequently, this feature enables HNE to accommodate substrates that have undergone methionine oxidation, which constitutes a hallmark post-translational modification of neutrophil signaling.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [1]
  1. Sanford-Burnham Medical Research Institute, La Jolla, CA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Wroclaw Univ. of Technology, Wroclaw (Poland)
Publication Date:
OSTI Identifier:
1193225
Report Number(s):
BNL--108110-2015-JA
Journal ID: ISSN 1554-8929; R&D Project: LS001
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
ACS Chemical Biology
Additional Journal Information:
Journal Volume: 10; Journal Issue: 4; Journal ID: ISSN 1554-8929
Publisher:
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE