(168i) Confinement Facilitated Protein-Protein Stacking: As Investigated By Neutron Scattering

Confinement of biomolecules in structured mesoporous materials can offer many advantages such as chemical and thermal stability, and resistance to degradation in both biological and synthetic systems. This has led to the application of protein confinement in implementation of this platform to applications as diverse as pharmaceutical formulation, bio-catalysis and sensing. A fundamental understanding of protein behaviour under confinement is paramount to design the best mesoporous host for a particular application. While many studies have linked changes in confined secondary structure and enzymatic activity, the understanding of overall confined protein tertiary structure and orientation under confinement is only partially understood. Here, we discuss recent advances elucidated via small-angle neutron scattering (SANS), using protein-loaded mesoporous silica materials known to exhibit a link between a better preserved confined secondary structure and higher enzymatic activity in narrow pores in which the curved surface interacts electrostatically with the enzyme¹. SANS enabled the general behaviour of two model proteins, representing distinct electrostatic conditions, to be observed over three confinement geometries in both the Henry and high concentration adsorption regimes. This analysis results in the observation of protein-protein stacking, which is driven by protein coordination that is facilitated by the geometry of the confining mesopores and the protein loading concentration.

References: [1] Sang L-C, Coppens M-O. Effects of surface curvature and surface chemistry on the structure and activity of proteins adsorbed in nanopores. Phys Chem Chem Phys. 2011;13(14):6689