9fic

From Proteopedia

High-resolution X-ray structure of human PC1/3 (PCSK1) prodomain R77A,R80A,R81A triple-mutant

Structural highlights

9fic is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.3Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

NEC1_HUMAN Obesity due to prohormone convertase I deficiency. The disease is caused by variants affecting the gene represented in this entry.

Function

NEC1_HUMAN Involved in the processing of hormone and other protein precursors at sites comprised of pairs of basic amino acid residues. Substrates include POMC, renin, enkephalin, dynorphin, somatostatin, insulin and AGRP.[UniProtKB:P63239]

Publication Abstract from PubMed

Proprotein convertases (PCs), including furin and PC1/3 among nine mammalian homologues, mediate the maturation of numerous secreted substrates by proteolytic cleavage. Disbalance of PC activity is associated with diseases like cancer, fibrosis, neurodegeneration and infections. Therefore, PCs are promising drug targets for the treatment of many diseases. However, the highly conserved active site of PCs complicates the development of specific inhibitors. Here we investigate the activation mechanism of PCs using X-ray crystallography and biochemical methods. The structure-based optimization of the multibasic secondary cleavage site loop not only prevents the prodomain's proteolytic cleavage but also increases its inhibition of furin. Combination of cleavage-resistant PC1/3-prodomain variants and a furin-specific nanobody in fusion proteins reveal very potent inhibitors (K(i) = 1.2 pM) with a more than 25,000-fold higher specificity for furin compared to the closely related PC-member PCSK5. Such fusion proteins effectively suppress the replication of a furin-dependent H7N7-influenza virus in cell-based assays.

Structural insights into proprotein convertase activation facilitate the engineering of highly specific furin inhibitors.,Klaushofer R, Bloch K, Eder LS, Marzaro S, Schubert M, Bottcher-Friebertshauser E, Brandstetter H, Dahms SO Nat Commun. 2025 Sep 2;16(1):8206. doi: 10.1038/s41467-025-63479-y. PMID:40897699^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Klaushofer R, Bloch K, Eder LS, Marzaro S, Schubert M, Böttcher-Friebertshäuser E, Brandstetter H, Dahms SO. Structural insights into proprotein convertase activation facilitate the engineering of highly specific furin inhibitors. Nat Commun. 2025 Sep 2;16(1):8206. PMID:40897699 doi:10.1038/s41467-025-63479-y