Grabowska O, Samsonov SA, Chmurzyński L, Wyrzykowski D, Żamojć K. Investigation of hexacyanoferrate(II)/(III) charge-dependent interactions with
bovine and human serum albumins.
Spectrochim Acta A Mol Biomol Spectrosc 2023;
293:122505. [PMID:
36809739 DOI:
10.1016/j.saa.2023.122505]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/21/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
In the present paper, the binding interactions of highly negative-charged ions, namely hexacyanoferrates(II/III), i.e. [Fe(CN)6]4- and [Fe(CN)6]3- with bovine and human serum albumins (BSA and HSA, respectively) have been studied for the first time in an aqueous solution (10 mM cacodylate buffer of pH 7.0) using steady-state fluorescence spectroscopy, isothermal titration calorimetry, and CD spectroscopy supported by molecular dynamics-based computational approaches. The Stern-Volmer equation as well as its modifications suggested that hexacyanoferrates(II/III) effectively quenched the intrinsic fluorescence of the albumins through a static mechanism. The proteins under study possess only one binding site on the surface capable of binding one mole of hexacyanoferrates(II/III) ions per one mole of albumin (HSA or BSA). The formation of albumin complexes is an enthalpy-driven process (|ΔHITC| > |TΔSITC|). The strength of the interactions depends mainly on the type of albumin, and changes as follows: BSA-K3[Fe(CN)6] ∼ BSA-K4[Fe(CN)6] > HSA-K3[Fe(CN)6] ∼ HSA-K4[Fe(CN)6]. Finally, potential binding sites of bovine and human serum albumins have been investigated and discussed based on a competitive fluorescence displacement assay (with warfarin and ibuprofen as site markers) and molecular dynamics simulations.
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