Ferritin is a ubiquitous protein with a crucial role in tick biology. Ticks digest large amounts of host blood and are exposed to an enormous amount of free iron, which has to be treated properly to avoid its toxicity. Two types of ferritin were discovered in the tick Ixodes ricinus – tagged as ferritin I and ferritin II [1]. Ferritin I is a globular protein composing 24 subunits (25kDa each) and forming a hollow-sphere complex. [2; 3]. Ferritin I functions as an intracellular scavenger of potentially toxic free iron and is capable to sequester up to 4 500 iron atoms [2]. The function of ferritin II is not entirely clear, but it probably plays a role in the transport of non-heme iron between the tick gut and the peripheral tissues. Silencing of ferritin II using RNA interference had a detrimental effect on tick development and reproduction [1]. The vaccination of mammalian hosts with recombinant ferritin II revealed its promising potential as an efficient anti-tick vaccine [4].
This study focuses on the molecular, biochemical and structural characterization of ferritin II from Ixodes ricinus. We have cloned ferritin II into three E. coli expression vectors (pET100, pET-SUMO and pASK-37+), and optimized its production in various expression cells and conditions (e.g., temperature, times and concentrations of inducer). To obtain enough amount of pure recombinant ferritin II for following structural studies, we will concentrate on improving protein isolation and purification.
1. Hajdusek, O., Sojka, D., Kopacek, P., Buresova, V., Franta, Z., Sauman, I., Winzerling, J., & Grubhoffer, L. (2009). Knockdown of proteins involved in iron metabolism limits tick reproduction and development. Proceedings of the National Academy of Sciences of the United States of America, 106(4).
2. Pham, D. Q., & Winzerling, J. J. (2010). Insect ferritins: Typical or atypical? Biochimica et biophysica acta, 1800(8), 824–833.3. H. J. Bunge, Texture Analysis in Materials Science. London: Butterworth. 1982.
3. Kopáček, P., Zdychová, J., Yoshiga, T., Weise, C., Rudenko, N., & Law, J. H. (2003). Molecular cloning, expression and isolation of ferritins from two tick species--Ornithodoros moubata and Ixodes ricinus. Insect biochemistry and molecular biology, 33(1), 103–113.
4. Hajdusek, O., Almazán, C., Loosova, G., Villar, M., Canales, M., Grubhoffer, L., Kopacek, P., & de la Fuente, J. (2010). Characterization of ferritin 2 for the control of tick infestations. Vaccine, 28(17), 2993–2998
This research is supported by the Czech Science Foundation (GACR 21-08826S) and ERDF CZ.02.1.01/0.0/0.0/15_003/0000441