9VZU

Crystal structure of EPIC1 from Phytophthora nicotianae

This is a non-PDB format compatible entry.

Summary for 9VZU

• Entry DOI: 10.2210/pdb9vzu/pdb
• Descriptor: Extracellular cystatin-like protease inhibitor (2 entities in total)
• Functional Keywords: epic1, plant immune system, host immune suppresion, immune system
• Biological source: Phytophthora nicotianae (black shank of tobacco agent)
• Total number of polymer chains: 6
• Total formula weight: 69190.18

Authors

Kang, Y.J.,Park, H.H. (deposition date: 2025-07-23, release date: 2026-07-08)

Primary citation

Lee, G.H.,Kang, Y.J.,Jin, H.B.,Park, H.H.
Two different domain swapped dimer structures were revealed by crystal structure of EPIC1 from Phytophthora nicotianae.
Biochem.Biophys.Res.Commun., 781:152543-152543, 2025

PubMed Abstract: Cysteine protease inhibitors such as cystatins are crucial regulators of proteolytic activity involved in immunity, host-pathogen interactions, and cellular homeostasis. EPIC1, a cystatin-like inhibitor secreted by plant pathogen, such as Phytophthora nicotianae, suppresses host immunity by targeting papain-like cysteine proteases. Here, we report the high-resolution crystal structure of EPIC1, revealing a domain-swapped dimer architecture in which structural elements are exchanged between monomers. Notably, we identified two distinct types of domain-swapped dimers, both stabilized by interdomain disulfide bonds-an unprecedented feature among pathogen-derived cystatin-like inhibitors. These covalent linkages are predicted to play a critical role in dimer formation and structural integrity. Our findings provide the first atomic-resolution structure of EPIC1 and uncover a novel dimerization mechanism that may contribute to its functional stability and specificity in the host environment.

PubMed: 40876292
DOI: 10.1016/j.bbrc.2025.152543

Experimental method

X-RAY DIFFRACTION (2.39 Å)