Thermodynamics of the Association of Aminoglycoside Antibiotics with Human Angiogenin

Abstract

Background: It is crucial for the body to maintain a firm balance between the inducers and inhibitors of angiogenesis, the process of proliferation of blood vessels from pre-existing ones. Human angiogenin (hAng) is a potent inducer of angiogenesis and the search for inhibitors has become a vital research area. Aminoglycosides are linked ring systems consisting of amino sugars and an aminocyclitol ring and are in use in clinical practices for a long time. These compounds have found clinical uses as antibacterial agents that inhibit bacterial protein synthesis. Objective: Gentamycin C1, Kanamycin A, Neomycin B, Paromomycin I, and Streptomycin A are commonly used aminoglycoside antibiotics that have been used for the present study. Among these, Neomycin has reported inhibitory activity against angiogenin-induced angiogenesis on the chicken chorioallantoic membrane. This study focuses on the thermodynamic parameters involved in the interactions of these antibiotics with hAng. Main Findings: Anti-ribonucleolytic effect of the antibiotics was observed qualitatively using an agarose gel-based assay, which shows that Neomycin exhibits the most efficient inhibition of hAng. Fluorescence quenching studies at different temperatures, using Stern-Volmer and van’t Hoff equations provide information about the thermodynamics of binding, which furthermore highlights the higher binding constant of Neomycin. Docking studies provide an insight into the participation of specific amino acid residues with the aminoglycoside antibiotics. It was observed that the antibiotics preferably interact with the nuclear translocation site, except Streptomycin, which interacts with the ribonucleolytic site of the protein with low affinity.