4wvp
From Proteopedia
Crystal structure of an activity-based probe HNE complex
Structural highlights
Disease[ELNE_HUMAN] Defects in ELANE are a cause of cyclic haematopoiesis (CH) [MIM:162800]; also known as cyclic neutropenia. CH is an autosomal dominant disease in which blood-cell production from the bone marrow oscillates with 21-day periodicity. Circulating neutrophils vary between almost normal numbers and zero. During intervals of neutropenia, affected individuals are at risk for opportunistic infection. Monocytes, platelets, lymphocytes and reticulocytes also cycle with the same frequency.[1] [2] Defects in ELANE are the cause of neutropenia severe congenital autosomal dominant type 1 (SCN1) [MIM:202700]. SCN1 is a disorder of hematopoiesis characterized by a maturation arrest of granulopoiesis at the level of promyelocytes with peripheral blood absolute neutrophil counts below 0.5 x 10(9)/l and early onset of severe bacterial infections.[3] Function[ELNE_HUMAN] Modifies the functions of natural killer cells, monocytes and granulocytes. Inhibits C5a-dependent neutrophil enzyme release and chemotaxis.[4] Publication Abstract from PubMedHuman 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. The Elastase-PK101 Structure: Mechanism of an Ultrasensitive Activity-based Probe Revealed.,Lechtenberg BC, Kasperkiewicz P, Robinson H, Drag M, Riedl SJ ACS Chem Biol. 2015 Jan 22. PMID:25581168[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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