Dynamic and structural insights into tick serpin from Ixodes ricinus

Ixodid ticks have a crucial impact on people and domestic animals worldwide. These parasites also pose a serious threat to livestock. To date, vaccination of hosts against ticks is a safer, more sustainable alternative to chemical control of ticks and the disease agents they transmit. Because of the...

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Bibliographic Details
Published in:	Journal of biomolecular structure & dynamics Vol. 38; no. 8; pp. 2296 - 2303
Main Authors:	Pongprayoon, Prapasiri, Niramitranon, Jitti, Kaewhom, Phaitoon, Kaewmongkol, Sarawan, Suwan, Eukote, Stich, Roger W., Jittapalapong, Sathaporn
Format:	Journal Article
Language:	English
Published:	England Taylor & Francis 23-05-2020
Subjects:	Ixodes ricinus molecular dynamics simulations serpins Ticks molecular dynamics simulations Ixodes ricinus Ticks serpins
Online Access:	Get full text
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Summary:	Ixodid ticks have a crucial impact on people and domestic animals worldwide. These parasites also pose a serious threat to livestock. To date, vaccination of hosts against ticks is a safer, more sustainable alternative to chemical control of ticks and the disease agents they transmit. Because of their roles in tick physiology, serpins (serine protease inhibitors) from tick saliva are among the candidates for anti-tick vaccines. Inhibitory serpins employ a suicide inhibition mechanism to inhibit proteases, where the serpin reactive centre loop (RCL) is cleaved, by the targeted protease, and then inserted into the main β-sheet of the serpin. This causes a massive conformational change called the 'stressed to relaxed' (S→R) transition, leading to the breakdown of serpin into two regions (core domain and cleaved polypeptide). Recently, the first tick serpin crystal structure from Ixodes ricinus in R-state was reported. We thus employed molecular dynamics simulations to better understand serpin structure and dynamics in atomic detail. Overall, R-state serpin showed high rigidity, especially the core domain. The most flexible region is the terminal of the cleaved polypeptide, due to its high-water exposure, while the rest of the cleaved polypeptide is stably trapped behind the core domain. T363, D367 and N375 are found to play a vital role in protein-protein attachment. This finding can be used to explain the high stability of the R-state serpin at the atomic level and provides insight into this tick serpin which will be useful for rational anti-tick vaccine development. Abbreviations MD Molecular Dynamics RCL Reactive centre loop Communicated by Ramaswamy H. Sarma
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0739-1102 1538-0254
DOI:	10.1080/07391102.2019.1630003