A cysteine protease of Babesia microti and its interaction with tick cystatins

• Published in: Parasitology research (1987) Vol. 119; no. 9; pp. 3013 - 3022
• Main Authors: Wei, Nana, Du, Yanfang, Lu, Jinmiao, Zhou, Yongzhi, Cao, Jie, Zhang, Houshuang, Gong, Haiyan, Zhou, Jinlin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2020; Springer; Springer Nature B.V
• Subjects: Amino acid sequence; Analysis; Arachnids; Babesia; Babesia microti; Babesiosis; Biomedical and Life Sciences; Biomedicine; Cysteine; Cysteine proteinase; Cystine; Enzymatic activity; Ethylenediaminetetraacetic acid; Fever; Hemolytic anemia; Immunology; Medical Microbiology; Microbiology; Molecular weight; Open reading frames; Proteases; Proteinase; Protozoology - Original Paper; Massachusetts; China; Cysteine protease; Tick cystatin; BmCYP
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-020-06818-w

Babesiosis is a tick-borne protozoonosis caused by Babesia , which can cause fever, hemolytic anemia, hemoglobinuria, and even death. Babesia microti is a parasite found in rodents and can be pathogenic to humans. In this study, the full-length cDNA of a B. microti cysteine protease (BmCYP) was expressed and the recombinant rBmCYP protein analyzed and characterized. BmCYP is encoded by an ORF of 1.3 kb, with a predicted molecular weight of 50 kDa and a theoretical pI of 8.5. The amino acid sequence of BmCYP exhibits an identity of 32.9 to 35.2% with cysteine proteases of Babesia ovis , Babesia bovis , and Theileria , respectively. The results of the proteinase assays show that rBmCYP has cysteine protease enzymatic activity. In addition, we demonstrate that tick cystatins rRhcyst-1 and rRhcyst-2 were able to effectively inhibit the activity of rBmCYP; the inhibition rates were 57.2% and 30.9%, respectively. Tick cystatins Rhcyst-1 and Rhcyst-2 were differentially expressed in ticks that fed on Babesia -infected mice relative to non-infected control ticks. Our results suggest that BmCYP is a functional enzyme with cysteine protease enzymatic activity and may be involved in tick- B. microti interactions.