Colloids and Surfaces B: Biointerfaces 155 (2017) 159–165 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces j o ur nal ho me pa ge: www.elsevier.com/locate/colsurfb Protocols Interaction of -synuclein with Rhus typhina tannin – Implication for Parkinson’s disease Szymon Sekowski a,∗ , Maksim Ionov b , Nodira Abdulladjanova c , Rustam Makhmudov c , Saidmukhtar Mavlyanov c , Katarzyna Milowska b , Maria Bryszewska b , Maria Zamaraeva a a Department of Biophysics, Laboratory of Molecular Biophysics, Faculty of Biology and Chemistry, University of Bialystok, 15-950 Bialystok, Poland b Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland c Institute of Bioorganic Chemistry, Academy of Science of Republic of Uzbekistan, 100143, Tashkent, Uzbekistan a r t i c l e i n f o Article history: Received 22 January 2017 Received in revised form 29 March 2017 Accepted 4 April 2017 Available online 10 April 2017 Keywords: -Synuclein Rhus typhina tannin Parkinson’s disease Human serum albumin a b s t r a c t The etiology of Parkinson’s disease (PD) relates to -synuclein, a small protein with the ability to aggre- gate and form Lewy bodies. One of its prevention strategies is inhibition of -synuclein oligomerization. We have investigated the interaction of -synuclein and human serum albumin with 3,6-bis-O-di-O- galloyl-1,2,4-tri-O-galloyl--d-glucose (a tannin isolated from the plant Rhus typhina). Using fluorescence spectroscopy method we found that this tannin interacts strongly with -synuclein forming complexes. Circular dichroism analysis showed a time-dependent inhibition of -synuclein aggregation in the pres- ence of the tannin. On the other hand, 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl--d-glucose had a much stronger interaction with human serum albumin than -synuclein. The calculated binding constant for tannin-protein interaction was considerably higher for albumin than -synuclein. This tannin inter- acted with albumin through a “sphere of action” mechanism. The results lead to the conclusion that 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl--d-glucose is a potent preventive compound against Parkin- son’s disease. However, this tannin interacts very strongly with human serum albumin, significantly reducing the bioavailability of this compound. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by symptoms of tremor, bradykinesia and rigidity of muscles [1,2]. Irrespective of etiology of the disease, PD is connected with the appearance of cytoplasmic and neuritic fibrillar inclusions, known as Lewy bodies (LB), in surviving dopaminergic neurons, and Lewy neuritis as well as their death, mainly in the substantia nigra pars compacta [2]. Aggregation of the presynap- tic protein, -synuclein, is assumed to underlie PD pathogenesis as its oligomeric forms are found in the brains of patients. - synuclein (-syn.) is a small protein of 140 amino acids, divided into 3 major domains: amphipathic N-terminal region, NAC (non- amyloidogenic component) domain and C-terminal region [3]. The physiological role of -syn. is not completely understood. Its local- ization in neuronal synaptic terminal and ability to interact with membranes indicates -synuclein involvement in neurotransmis- sion. ∗ Corresponding author. E-mail addresses: s.sekowski@uwb.edu.pl, sekowski100@vp.pl (S. Sekowski). It is known that this small protein is involved in a synaptic plas- ticity, and regulation of dopamine release and re-uptake [4]. -syn. can also influence on the concentration of dopamine by regulating the activity of tyrosine hydroxylase, which is involved in dopamine synthesis [5]. Despite its important physiological role, -syn. also has neurotoxic effects due to its ability to aggregate. Structural changes of -syn. due to several missense mutation or increase of its concentration results in overexpression, leading to the forma- tion different oligomers [1–3]. Aggregates of -syn. may be secreted and captured by other cells. It is assumed that fibrillar forms of - syn. serve as places for aggregation of soluble monomeric protein [6]. The mechanisms of neurotoxicity of the aggregated forms of - syn. remain the subject of debate as they are not fully understood. Oligomeric -syn. can probably form a pore-like structure, cause overload of Ca 2+ and increase the formation of ROS, which in turn triggers cell death [7]. Fibrils of -syn. are structural components not only of Lewy bodies in Parkinson’s disease, but are found in other disorders; for example, aggregation has been observed in dementia with Lewy bodies, multiple systems atrophy and the Lewy body variant of Alzheimer’s disease, all of which that are known collectively as –synucleinopathies [6]. Inhibition of polypeptide aggregation is http://dx.doi.org/10.1016/j.colsurfb.2017.04.007 0927-7765/© 2017 Elsevier B.V. All rights reserved.