Kinetics of protein unfolding at interfaces

Abstract

The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces.

Functional improvements in bovine serum albumin–fucoidan conjugate through the Maillard reaction

“…Native BSA decreased the surface tension of water (buffer only, about 69 mN/m) with increasing protein concentration due to an amphiphilic effect (Kim et al, 2010). In addition, BSA adsorbed very rapidly on the air-water interface and partially unfolded upon adsorption, because BSA was categorized as soft protein, showing reduction of surface tension (Yano, 2012). At a protein concentration of 1mg/ml, native BSA lowered surface tension of aqueous buffer (water) to 57.05 ± 2.92 mN/m, 56.40 ± 0.87 mN/m and 58.71 ± 1.60 mN/m at pH 3, pH 5, and pH 7, respectively.…”

Structure and Orientation of Interfacial Proteins Determined by Sum Frequency Generation Vibrational Spectroscopy

“…Extensive researches have been performed to gain insight into interfacial protein structures and properties using a number of techniques, such as surface plasmon resonance (Yano, 2012), nuclear magnetic resonance (NMR) (Judge & Watts, 2011), atomic force microscopy (Fotiadis, 2012), and so on. The applications of these techniques (and others) to the study of the interactions between proteins and surface can be found in previous review articles (Fotiadis, 2012;Judge & Watts, 2011;Yano, 2012).…”

Single-molecule resolution of protein structure and interfacial dynamics on biomaterial surfaces

“…Such limitations can lead to misinterpretations of apparent interfacial phenomena, which are used to explain the biocompatibility of biomaterials. For example, conventional biophysical methods often find that the average surface protein conformation relaxes from native-like to nonnative-like upon surface adsorption, which is interpreted as evidence for unfolding (11)(12)(13)(14). However, the time scales over which these conformational changes reportedly occur are orders of magnitude longer than typical surface residence times of isolated proteins (15), suggesting that the picture of surfaceinduced spreading may be oversimplified.…”