Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin

• Published in: Chemical physics 2013-08, Vol.422, p.88-97
• Main Authors: Roche, Camille J., Dantsker, David, Heller, Elizabeth R., Sabat, Joseph E., Friedman, Joel M.
• Format: Article
• Language: English
• Subjects: Geminate recombination; Hemoglobin; Hydration; Protein dynamics; Reverse micelles; Solvent slaving
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2013.04.006

[Display omitted] •Reverse micelle encapsulated hemoglobin: a system for probing hydration and dynamics.•PEG can be used to tune the water content of reverse micelles.•A unique system suitable for combined NMR and optical study of dynamics.•Reverse micelles can be used to test solvent slaving theory. Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to manipulate water content. Hydration properties are probed using the water-sensitive fluorescence from Hb bound pyranine and covalently attached Badan. Protein dynamics are probed through ligand recombination traces derived from photodissociated carbonmonoxy hemoglobin on a log scale that exposes the potential role of both α and β solvent fluctuations in modulating protein dynamics. The results open the possibility of probing hydration level phenomena in this system using a combination of NMR and optical probes.