Protein Binding of Benzofuran Derivatives: A CD Spectroscopic and In Silico Comparative Study of the Effects of 4-Nitrophenyl Functionalized Benzofurans and Benzodifurans on BSA Protein Structure

Abstract

Benzofuran derivatives are synthetic compounds that are finding an increasing interest in the scientific community not only as building blocks for the realization of new materials, but also as potential drugs thanks to their ability to interact with nucleic acids, interfere with the amyloid peptide aggregation and cancer cell cycle. However, their ability to interact with proteins is a theme still in need of investigation for the therapeutic importance that benzofurans could have in the modulation of protein-driven processes and for the possibility of making use of serum albumins as benzofurans delivery systems. To this scope, we investigated the protein binding ability of two 4-nitrophenyl-functionalized benzofurans previously synthesized in our laboratory and herein indicated as BF1 and BDF1, which differed for the number of furan rings (a single moiety in BF1, two in BDF1), using bovine serum albumin (BSA) as a model protein. By circular dichroism (CD) spectroscopy we demonstrated the ability of the two heteroaromatic compounds to alter the secondary structure of the serum albumin leading to different consequences in terms of BSA thermal stability with respect to the unbound protein (ΔTm > 3 °C for BF1, −0.8 °C for BDF1 with respect to unbound BSA, in PBS buffer, pH 7.5) as revealed in our CD melting studies. Moreover, a molecular docking study allowed us to compare the possible ligand binding modes of the mono and difuranic derivatives showing that while BF1 is preferentially housed in the interior of protein structure, BDF1 is predicted to bind the albumin surface with a lower affinity than BF1. Interestingly, the different affinity for the protein target predicted computationally was confirmed also experimentally by fluorescence spectroscopy (kD = 142.4 ± 64.6 nM for BDF1 vs. 28.4 ± 10.1 nM for BF1). Overall, the above findings suggest the ability of benzofurans to bind serum albumins that could act as their carriers in drug delivery applications.

CD, UV, and In Silico Insights on the Effect of 1,3-Bis(1′-uracilyl)-2-propanone on Serum Albumin Structure

“…Circular dichroism (CD) spectra were recorded on a Jasco J-715 spectropolarimeter equipped with a Jasco Peltier PTC-423S/15 temperature controller (Jasco Europe S.r.l, Cremella, Italy) using a Hellma-238-QS tandem quartz cell (2 × 0.4375 cm from Hellma Italia S.r.l., Milano, Italy) according to the previous literature experiments [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ] with a response time of 1 s, a scanning speed of 100 nm min −1 , and a bandwidth of 2.0 nm in the 205–260 nm wavelength range. All the spectra were averaged over three scans.…”

Fluorescence in depth: integration of spectroscopy and imaging with Raman, IR, and CD for advanced research

“…This finding was further corroborated using fluorescence spectroscopy. Based on these findings, it was inferred that serum albumins have the potential to act as drug carriers for transporting benzofuran derivatives [197]. In another drug delivery research, Paul investigated the interaction between 3,5-diiodosalicylic acid (3,5-DISA), rectal insulin delivery, and HSA.…”

“…• Caries detection in dental research [55]. • Assessing the interaction of benzofuran derivatives with proteins for drug delivery purposes [197].…”