Non-Covalent NIR Fluorescent Labels for Human Serum Albumin Bound to Mangiferin
Binding constants and other binding characteristics of small molecules to biomolecules are controlled by several factors, such as hydrophobicity, charge, size, etc. Dye binding to biomolecules has been used in analytical chemistry for biomolecule characterization, non-covalent labeling and other applications. Determining and optimizing binding properties facilitates the design of dyes for non-covalent labeling applications. Longer wavelength probes and reporters have several advantages such as lower background interference especially important in complex biological samples. Carbocyanines are relatively easy to synthesize and can be designed to achieve particular spectroscopic and chemical properties. During this work two polymethine dyes (NIR) whose binding to serum albumins were characterized earlier were used to determine if they can be used as non-covalent reporters during mangiferin (MGF) binding to HSA. MGF binding was characterized utilizing spectral changes in Trp-214 residue. NIR dyes that do not change MGF binding and does not compete with MGF binding can be used as reporting probes or tracers for the MGF-HSA complex potentially affording low detection limits. The utility of these dyes as tracers for biomolecules bound to small molecules were evaluated.
Index Terms- Biomolecular Binding, Human Serum Albumin, Mangiferin, Near Infrared Dyes