Polyamine Analogues Bind Human Serum Albumin

Abstract

Polyamine analogues show antitumor activity in experimental models and their ability to alter activity of cytotoxic chemotherapeutic agents in breast cancer is well documented. Association of polyamines with nucleic acids and protein is included in their mechanism of action. The aim of this study was to examine the interaction of human serum albumin (HSA) with several polyamine analogues such as 1,3,7,11,7,11,15, in aqueous solution at physiological conditions, using a constant protein concentration and various polyamine contents (μM to mM). FTIR, UVvisible and CD spectroscopic methods were used to determine the polyamine binding mode and the effects of polyamine complexation on protein stability and secondary structure.Structural analysis showed that polyamines bind non-specifically (H-bonding) via polypeptide polar groups with binding constants of K 333 = 9.30 × 10 3 M −1 , K BE-333 = 5.63 × 10 2 M −1 and K BE-3333 = 3.66 × 10 2 M −1 . The protein secondary structure showed major alterations with reduction of α-helix from 55% (free protein) to 43-50% and increase of β-sheet from 17% (free protein) to 29-36% in the 333-, BE-333-and BE-3333 complexes, indicating a partial protein unfolding upon polyamine interaction. HSA structure was less perturbed by polyamine analogues than those of the biogenic polyamines.

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“…The fluorescence enhancement is attributable to a combination of processes including enhanced absorption and modification of the decay rate of the molecule, and enhanced coupling efficiency of the fluorescent emission to the far field 23. As shown in Figure 4 A, the fluorescence intensity of hemoglobin increased with the addition of C‐GNRs, which was different from the previous findings that the protein fluorescence quenching occurred with the binding of nanomaterials 24, 25. When the fluorescence intensity at the maximum emission wavelength (334 nm) was evaluated, it was found that F 0 / F value (the ratio between the protein fluorescence intensity without and with the addition of C‐GNRs) was negatively linearly related with the incubation concentrations of C‐GNRs.…”

Molecular dynamics simulation studies of betulinic acid with human serum albumin

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A Short Review on the Delivery of Breast Anticancer Drug Tamoxifen and its Metabolites by Serum Proteins

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