Conformational transition of the Ixodes ricinus salivary serpin Iripin-4

0572377 - BC 2024 RIV GB eng J - Journal Article
Kascaková, B. - Kotál, Jan - Havlíčková, P. - Vopatková, V. - Prudnikova, T. - Grinkevich, P. - Kutý, M. - Chmelař, J. - Smatanová, I.K.
Conformational transition of the Ixodes ricinus salivary serpin Iripin-4.
Acta Crystallographica Section D-Structural Biology. Roč. 79, MAY (2023), s. 409-419. ISSN 2059-7983. E-ISSN 2059-7983
Institutional support: RVO:60077344
Keywords : serpins * Iripin-4 * X-ray structure * native conformation * cleaved conformation * Ixodes ricinus
OECD category: Microbiology
Impact factor: 2.2, year: 2022
Method of publishing: Open access
https://scripts.iucr.org/cgi-bin/paper?S2059798323002322

Iripin-4, one of the many salivary serpins from Ixodes ricinus ticks with an as-yet unexplained function, crystallized in two different structural conformations, namely the native partially relaxed state and the cleaved serpin. The native structure was solved at a resolution of 2.3 angstrom and the structure of the cleaved conformation was solved at 2.0 angstrom resolution. Furthermore, structural changes were observed when the reactive-centre loop transitioned from the native conformation to the cleaved conformation. In addition to this finding, it was confirmed that Glu341 represents a primary substrate-recognition site for the inhibitory mechanism. The presence of glutamate instead of the typical arginine in the P1 recognition site of all structurally characterized I. ricinus serpins (PDB entries 7b2t, 7pmu and 7ahp), except for the tyrosine in the P1 site of Iripin-2 (formerly IRS-2, PDB entry 3nda), would explain the absence of inhibition of the tested proteases that cleave their substrate after arginine. Further research on Iripin-4 should focus on functional analysis of this interesting serpin.
Permanent Link: https://hdl.handle.net/11104/0345554