Proteins and Interfaces: Stability and Function

Proteins are exposed to a multitude of different surfaces and chemistries in vivo and yet, they must retain their stability in order to function.  However, conversion of soluble native proteins into beta-sheet-rich structured aggregates, such as amyloid and prion deposits can occur at interfaces.  Protein stability and activity is also essential for use in various medical and analytical devices, such as biosensors, biocatalytic chips, biocompatible materials for implants, drug delivery vehicles, tissue engineering and beads or membranes for bioseparations.  Although a vast experimental literature exists on the adsorption of specific proteins to various solid substrates under defined conditions, difficulties in determining the underlying reasons for the loss of stability and function remain.  Many researchers have addressed particular aspects of protein behavior at interfaces through experiment, theory and molecular simulation.  Here, we review recent results on protein stability and activity on solid heterogeneous and homogeneous substrates, demonstrate the effect of surface chemistry and roughness on protein aggregation, describe a novel method to probe unfolding of a monolayer of tethered proteins and introduce new NMR titration results with chromatographic data in order to study the nature of protein adsorption in multimodal chromatography.  We also mention the use of single molecule force spectroscopy to determine molecular interactions in the nuclear pore complex (NPC).  Tethered fibril-like proteins that contain intrinsically disordered domains interact with carrier proteins that determine selectivity.  Finally, we introduce a new high-throughput synthesis and screening method to identify protein resistant surfaces.