Έρευνα / Ερευνητικές κατευθύνσεις / Δομική Βιολογία και Μοριακή Μοντελοποίηση

Πρωτεϊνική Βιοχημεία

Δρ. Αικατερίνη Τσιτσάνου

Group leader

Δρ. Αικατερίνη ΤσιτσάνουΕντεταλμένη Ερευνήτρια

Group members

Γιώργος ΣωτηρούδηςMSc, Ειδικό Επιστημονικό & Τεχνικό Προσωπικό

Dr K.E. Tsitsanou’s research focuses on elucidating the interaction mechanisms between bioactive molecules/drugs and protein/enzyme targets of pharmaceutical and biotechnological importance. Her team employs recombinant DNA techniques, heterologous protein expression systems, and advanced protein purification technologies to produce high-quality protein samples, including isotopically labeled proteins suitable for macromolecular NMR studies. Furthermore, she applies in vitro enzyme kinetics and biochemical binding assays to discover bioactive molecules and investigate their mechanism of action, as well as X-ray protein crystallography to identify the key ligand structural features that drive their specific binding. Through participation in several research projects and COST actions, Dr. Tsitsanou has established an extensive network of collaborators in Greece and internationally, specializing in thermodynamic analysis, NMR, cryo-EM, in silico modeling, and behavioral studies.

Main Scientific Directions

Leishmania parasites, transmitted to mammalian hosts through the bite of blood-feeding sandflies, cause leishmaniasis, recognized by the World Health Organization (WHO) as one of the most important tropical diseases and a serious global health concern. Currently, no human vaccine is available, and existing chemotherapy options are limited by toxicity issues and the growing emergence of drug-resistant parasite strains. This highlights the urgent need to develop new, targeted, and safe antiparasitic compounds. Our objective is to exploit both known and novel protein targets for antiparasitic drug development. Among these, selected members of the Leishmania phosphatase family are recombinantly produced and further exploited as targets for the discovery of novel inhibitors through in vitro screening approaches.

Through establishment of collaborations within the framework of the COST Action “One Health drugs against parasitic vector-borne diseases in Europe and beyond” and the Department of Microbiology & Bioimaging-Light Microscopy Facility of the Hellenic Pasteur Institute, the team aspires to contribute to the discovery of potent anti-Leishmania agents by providing novel proteins as targets for screening against diverse compound libraries.

Furthermore, Dr. Tsitsanou plans to expand her research to include novel protein targets from other protozoan parasites, aiming to facilitate the development of novel agents against malaria, trypanosomiasis, and other parasitic diseases.

Niemann-Pick type C2 (NPC2) proteins have emerged as a novel class of binding and transport proteins for semiochemicals in arthropods, particularly in ticks and mites, but also in agriculturally important insects such as the worker Japanese carpenter ant (Camponotus japonicus) and the bollworm (Helicoverpa armigera), where they are believed to be involved in social communication and host-plant recognition.

They serve a complementary or alternative role to odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), expanding the known molecular repertoire of chemoreception in insects. As such, NPC2 proteins represent promising targets for the development of protection strategies in both livestock and crop production.

Dr. Tsitsanou’s research focuses on the biochemical, functional and structural characterization of insects Niemann-Pick type C2 (NPC2) proteins and selected OBPs from crop-infesting insects of significant agricultural importance. These proteins are investigated as molecular targets for structure-based discovery of novel insect behavioral disruptors, repellents or attractants.

National

H. Boleti, Department of Microbiology, Hellenic Pasteur Institute
K. Iatrou, Institute of Biosciences & Applications, NCSR-Demokritos
Luc Swevers, Institute of Biosciences & Applications, NCSR-Demokritos
G. Skretas, Institute for Bio-innovation, Biomedical Sciences Research Center “Alexander Fleming”
E. Eliopoulos, Biotechnology Department, Agricultural University of Athens
Α. Michaelakis, Department of Entomology and Agricultural Zoology, Benaki Phytopathological Institute
V. Roussis, Department of Pharmacy, National & Kapodistrian University of Athens.
Prof. P. Giastas, Biotechnology Department, Agricultural University of Athens
S. Zographos, ICB-NHRF
E. Chrysina, ICB-NHRF
T. Calogeropoulou, ICB-NHRF
N. Chondrogianni, ICB-NHRF
Μ. Zervou, ICB-NHRF

International

D. Fessas, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Italy
H. Pérez-Sánchez, BIO-HPC Research Group, Universidad Católica de Murcia, Spain
R. Sowdhamini, National Centre for Biological Sciences, Karnataka, India
J.T. Huiskonen, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Finland

Publications in refereed journals

Mam, B.*, Tsitsanou, K.E.*, Liggri, P.G.V., Saitta, F., Stamati, E.C.V., Mahita, J., Leonis, G., Drakou, C.E., Papadopoulos, M., Arnaud, P., Offmann, B., Fessas, D., Sowdhamini, R. & Zographos, S.E. (2023). Influence of pH on indole-dependent heterodimeric interactions between Anopheles gambiae odorant-binding proteins OBP1 and OBP4. Int J Biol Macromol. 125422 (doi: 1016/j.ijbiomac.2023.125422 )
Liggri, P.G.V., Perez-Garrido, A., Tsitsanou, K.E., Dileep, K.V., Michaelakis, A., Papachristos, D., Perez-Sanchez, H. & Zographos, S.E. (2023). 2D finger-printing and molecular docking studies identified potent mosquito repellents targeting odorant binding protein 1. Insect Biochem Mol Biol. 157:103961 (doi:1016/j.ibmb.2023.103961)
Liggri, P.G.V., Tsitsanou, K.E., Stamati, E.C.V., Saitta, F., Drakou, C.E., Leonidas, D.D., Fessas, D. & Zographos, S.E. (2023). The structure of AgamOBP5 in complex with the natural insect repellents Carvacrol and Thymol: Crystallographic, fluorescence and thermodynamic binding studies. Int J Biol Macromol. 237, 124009 (doi: 1016/j.ijbiomac.2023.124009 ).
Kritsi, E., Liggri, P.G.V., Stamati, E.C.V., Tsitsanou, K.E., Zographos, S.E., Michaelakis, A., Papachristos, D. & Zoumpoulakis, P. (2022). A Combined Computational Methodology for the Discovery of Hit Compounds with Putative Insect Repellency Properties. 17, e202200271 (doi: 10.1002/cmdc.202200271 ).
Leonidas, D.D., Zographos, S.E., Tsitsanou, K.E., Skamnaki, V.T., Stravodimos, G. & Kyriakis, E. (2021). Glycogen phosphorylase revisited: extending the resolution of the R- and T-state structures of the free enzyme and in complex with allosteric activators. Acta Cryst. F77, 303-311 (doi: 1107/S2053230X21008542 )
Thireou, T., Kythreoti, G., Tsitsanou,E., Koussis, K., Drakou, C.E., Kinnersley, J., Kröber, T., Guerin, P.M., Zhou, J.J., Iatrou, K., Eliopoulos, E. & Zographos, S.E. (2018). Identification of novel bioinspired synthetic mosquito repellents by combined ligand-based screening and OBP-structure-based molecular docking. Insect Biochem Mol Biol. 98, 48-61 (doi: 10.1016/j.ibmb.2018.05.001)
Drakou, C.E., Tsitsanou, K.E., Potamitis, C., Fessas, D., Zervou, M. & Zographos, S.E. (2017). The crystal structure of the AgamOBP1•Icaridin complex reveals alternative binding modes and stereo-selective repellent recognition. Cell Mol Life Sc 74, 319-338 (doi:10.1007/s00018-016-2335-6)
Tsitsanou, K.E., Drakou, C.E., Thireou, T., Vitlin Gruber, A., Kythreoti, G., Azem, A., Fessas, D., Eliopoulos, E., Iatrou, K. & Zographos, S.E. (2013). Crystal and Solution Studies of the “Plus-C” Odorant-binding Protein 48 from Anopheles gambiae: CONTROL OF BINDING SPECIFICITY THROUGH THREE-DIMENSIONAL DOMAIN SWAPPING. Biol. Chem. 288, 33427-33438 (doi:10.1074/jbc.M113.505289)
Tsitsanou, K.E., Hayes, J.M., Keramioti, M., Mamais, M., Oikonomakos, N.G., Kato, A., Leonidas, D.D. & Zographos, S.E. (2013). Sourcing the affinity of flavonoids for the glycogen phosphorylase inhibitor site via crystallography, kinetics and QM/MM-PBSA binding studies: Comparison of chrysin and flavopiridol. Food Chem Toxicol. 61, 14-27 (doi: 1016/j.fct.2012.12.030)
Tsitsanou, K.E., Thireou, T., Drakou, C.E., Koussis, K., Keramioti, M.V., Leonidas, D.D., Eliopoulos, E., Iatrou, K. & Zographos, S.E. (2012). Anopheles gambiae odorant binding protein crystal complex with the synthetic repellent DEET: implications for structure-based design of novel mosquito repellents. Cell Mol Life Sci. 69, 283-297 (doi: 1007/s00018-011-0745-z)
Watson, K.A., Chrysina, E.D., Tsitsanou K.E., Zographos, S.E., Archontis, G., Fleet, G.W. & Oikonomakos, N.G. (2005). Kinetic and crystallographic studies of glucopyranose spirohydantoin and glucopyranosylamine analogs inhibitors of glycogen phosphorylase. Proteins 61, 966-983. (doi: 1002/prot.20653 )

Book Chapter

Zographos, SE*, Eliopoulos, E, Thireou T and Tsitsanou, KE (2018). OBP-structure-aided repellent discovery: An emerging tool towards the prevention of mosquito-borne diseases in CRC book series QSAR in Environmental and Health Sciences “Computational design of chemicals for the control of mosquitoes and their diseases“, Edited by James Devillers, Chapter 3, pp. 65-105. ISBN: 978-1498-7418-04 | Publisher

Short communications

Structural and biochemical studies of an odorant binding protein from the malaria vector Anopheles gambiae. Liggri, P., Tsitsanou, K. & Zografos, S., 44th FEBS Congress, From Molecules to Living Systems, 6‐11 July 2019, Krakow, Poland, FEBS OPEN BIO 9 (Suppl. 1), 269, P-27-070 (doi: 10.1002/2211-5463.12675)
Crystal structure of odorant binding protein 4 from Anopheles gambiae. Tsitsanou, K.E., Drakou, C.E & Zographos, S.E. European Chemoreception Research Organization (ECRO) XXI^st congress, 7-10 September 2011, Manchester, UK. Senses 37, A41.
AgamOBP1 crystal complex with DEET: a new molecular target for the design of novel mosquito repellents. Tsitsanou, K.E., Thireou, T., Drakou, C.E., Koussis, K., Eliopoulos, E., Iatrou, K. & Zographos, S.E. European Chemoreception Research Organization (ECRO) XXI^st congress, 7-10 September 2011, Manchester, UK. Senses 31, A41-42.