Structure of human neutrophil elastase in complex with a 5,8-dihydro[1,2,4]triazolo[4,3-a]pyrimidin-3(2H)-one inhibitor. Determined by X-ray diffraction at 1.14 Å resolution. Released 10 Dec 2025.
Explore 9SI4 in 3D Show helices and sheets RCSB PDB PDBe
9SI4 contains 9 α-helices and 23 β-strands across 1 chain. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.
| Element | Residues | Length | Sheet |
|---|---|---|---|
| β-strand | 17 | 1 | 1 |
| β-strand | 20-21 | 2 | 2 |
| α-helix | 22-23 | 2 | |
| β-strand | 30-35 | 6 | 3 |
| β-strand | 38-47 | 10 | 3 |
| β-strand | 50-53 | 4 | 3 |
| α-helix | 55-58 | 4 | |
| α-helix | 63-65 | 3 | |
| β-strand | 67-70 | 4 | 3 |
| β-strand | 74 | 1 | 4 |
| β-strand | 83-92 | 10 | 3 |
| β-strand | 96 | 1 | 5 |
| β-strand | 101 | 1 | 5 |
| β-strand | 105-109 | 5 | 3 |
| β-strand | 116 | 1 | 6 |
| β-strand | 119 | 1 | 6 |
| α-helix | 121-123 | 3 | |
| α-helix | 125-126 | 2 | |
| α-helix | 130-132 | 3 | |
| β-strand | 136-141 | 6 | 2 |
| β-strand | 144 | 1 | 7 |
| β-strand | 151 | 1 | 7 |
| β-strand | 154 | 1 | 4 |
| β-strand | 156-163 | 8 | 2 |
| β-strand | 172-175 | 4 | 2 |
| β-strand | 182 | 1 | 1 |
| β-strand | 191-194 | 4 | 2 |
| β-strand | 197-204 | 8 | 2 |
| α-helix | 215 | 1 | |
| β-strand | 216-220 | 5 | 2 |
| α-helix | 221-224 | 4 | |
| α-helix | 225-232 | 8 |
| Molecule | Chains | Type | Length | Organism | UniProt |
|---|---|---|---|---|---|
| Neutrophil elastase | A | protein | 218 | Homo sapiens | P08246 (AlphaFold model) |
>9SI4_1 Neutrophil elastase (chains A) IVGGRRARPHAWPFMVSLQLRGGHFCGATLIAPNFVMSAAHCVANVNVRAVRVVLGAHNL SRREPTRQVFAVQRIFENGYDPVNLLNDIVILQLNGSATINANVQVAQLPAQGRRLGNGV QCLAMGWGLLGRNRGIASVLQELNVTVVTSLCRRSNVCTLVRGRQAGVCFGDSGSPLVCN GLIHGIASFVRGGCASGLYPDAFAPVAQFVNWIDSIIQ
| ID | Name | Formula | Copies |
|---|---|---|---|
| NAG | 2-acetamido-2-deoxy-beta-D-glucopyranose | C8 H15 N O6 | 3 |
| FUC | alpha-L-fucopyranose | C6 H12 O5 | 1 |
| A1JN2 | methyl (5~{R})-5-[4-cyano-2-[2-(trimethyl-$l^{4}-azanyl)ethyl]phenyl]-7-methyl-… | C27 H28 F3 N6 O3 | 1 |
Design, Synthesis, and Biological Evaluation of the Novel Neutrophil Elastase Inhibitor CHF-6333 for the Inhaled Treatment of Bronchiectasis. Armani, E., Rizzi, A., Miglietta, D. et al. J Med Chem (2025) 68:24869-24889. DOI 10.1021/acs.jmedchem.5c02638 · PubMed
Other PDB entries of the same protein (UniProt P08246 (AlphaFold model), which also has an AlphaFold model), best resolution first:
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