Effective inhibition of thrombin by Rhipicephalus microplus serpin-15 (RmS-15) obtained in the yeast Pichia pastoris

Xu, Tao, Lew-Tabor, Ala and Rodriguez-Valle, Manuel (2016) Effective inhibition of thrombin by Rhipicephalus microplus serpin-15 (RmS-15) obtained in the yeast Pichia pastoris. Ticks and Tick-borne Diseases, 7 1: 180-187. doi:10.1016/j.ttbdis.2015.09.007


Author Xu, Tao
Lew-Tabor, Ala
Rodriguez-Valle, Manuel
Title Effective inhibition of thrombin by Rhipicephalus microplus serpin-15 (RmS-15) obtained in the yeast Pichia pastoris
Formatted title
Effective inhibition of thrombin by Rhipicephalus microplus serpin-15 (RmS-15) obtained in the yeast Pichia pastoris
Journal name Ticks and Tick-borne Diseases   Check publisher's open access policy
ISSN 1877-9603
1877-959X
Publication date 2016-02-01
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.ttbdis.2015.09.007
Open Access Status Not yet assessed
Volume 7
Issue 1
Start page 180
End page 187
Total pages 8
Place of publication Muenchen, Germany
Publisher Elsevier
Language eng
Formatted abstract
The cattle tick (Rhipicephalus microplus) affects cattle industries in tropical and subtropical countries because it is the vector of babesiosis and anaplasmosis which constitutes a threat to the health of cattle. During blooding feeding, ticks secrete saliva containing a complex of bioactive molecules into the injured site to evade host's defensive responses. Serine protease inhibitors (serpins) are important anti-haemostatic molecules present in tick saliva that are necessary for a successful blood feeding. Several serpin sequences have been reported in R. microplus but there is a gap of information about their functions during host–parasite interactions. In this study, the RmS-15 expressed in the yeast Pichia pastoris was characterised using kinetic assays and in vitro analysis. The inhibitory enzymatic assays conducted showed that RmS-15 is a physiological inhibitor of thrombin with a stoichiometric inhibition (SI) of 1.5 and high inhibition affinity with ka = 9.3 ± 0.5×104 M−1 s−1. RmS-15 delayed the clotting of plasma in a dose-dependent manner as determined in a recalcification time assay. Significant elevated ELISA titres were observed in tick resistant and susceptible cattle on day 28 after the tick infestation (p < 0.001). This data suggests direct contact of RmS-15 with the immune system of the host at the tick-feeding site. The present study contributed to the understanding of the biological functions of R. microplus serpins during host–parasite interactions which contributes to the design of future innovative methods for tick control.
Keyword Anticoagulant
Cattle ticks
R. microplus
Serpins
Thrombin inhibitors
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Alliance for Agriculture and Food Innovation
Official 2016 Collection
 
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Citation counts: TR Web of Science Citation Count  Cited 7 times in Thomson Reuters Web of Science Article | Citations
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