Chronopotentiometric Analysis of Single Histones and Histone Octamer at Charged Surfaces

Abstract

Histones play an essential role in the nucleosome structure and organization. The key role of highly positively charged histones is to stabilize negatively charged DNA inside the chromatin. Histones are basic proteins containing a large amount of electroactive residues, namely, arginine and lysine. Additionally, histone H3, on the contrary to other histones, contains cysteine residues. To understand more about the behavior of histones at charged surfaces and the influence of the electroactive amino acid residues content on the catalytic hydrogen evolution reaction, we studied histones using label‐free approaches, namely, chronopotentiometric stripping analysis (CPS) and impedance Cd–t curves. While CPS is sensitive to the structure and stability of proteins and their complexes, Cd–t curves reflect changes of the electrical double layer at the charged surface. Application of both label‐free methods appears useful for analysis of complex systems. Using a combination of these methods, we could discriminate between individual single core histones, their mixture, and their complex (octamer).