Physico-Chemical nanomaterials science

Sensitivity of the alkylsulfid-terminated difunctionalized iron(II) clathrochelate to a conformation of transport protein albumin

Chornenka N.V.1, Losytskyy M.2 , Kovalska V.B.2, Gumienna-Kontecka E.3

1 V.I. Vernadsky Institute of General and Inorganic Chemistry NASU, Kyiv, Ukraine.
e-mail: nina.v.chornenka@gmail.com
2 Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine.
3 Faculty of Chemistry, University of Wroclaw, Wroclaw, Poland.

	

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Fig.1. Structure of clathrochelate (a) and ICD spectra of the BSA – clathrochelate assemblies (b). 	
Iron(II) clathrochelates, which are the three-dimensional cage complexes containing an encapsulated Fe2+ ion, were shown to acquire an intensive circular dichroism signal – induced CD (ICD) spectra – upon binding to some proteins, particularly albumins. Changes in the shapes and in the intensities of these spectra reflect both the conformation transitions of proteins macromolecules and their structural alterations. Here, ICD response of alkylsulfid-terminated diribbed-difunctionalized iron(II) clathrochelate (Fig. 1a) on the presence of serum bovine albumin (BSA) at рН 7.9 (1, 2 at Fig. 1b) and pH 4.3 (3, 4 at Fig. 1b), and clathrochelate-to-BSA concentration ratios 1:2 (1, 3 at Fig. 1b) and 2:1 (2, 4 at Fig. 1b) was studied. While for pH 7.9 clathroshelate ICD spectra were similar for both protein concentrations and contained two positive (near 350 and 530 nm) and one negative (near 450 nm) maxima, in the case of pH 4.3 lower protein concentration leads to drastic changes in ICD spectrum, namely the mirror reflection of the bands. We believe that partial conformation transition of BSA macromolecule leads to appearing of additional sites on BSA macromolecule for clathrochelates binding at higher clathrochelate-to-BSA concentrations ratio. 

The project leading to these results has received Funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Qurie grant agreement No 778245.