Proteins are vital for life and perform a wide range of essential biochemical tasks in all living organisms. Cells of these organisms are hence under a constant pressure to maintain an optimal protein environment, assuring all proteins are correctly folded and functional.
Unfolded proteins are sticky and tend to form so-called protein aggregates with either themselves, other proteins or when binding to exposed surfaces within the cell. Aggregation mechanisms depend on both primary amino acid sequence of the protein and external environment such as pH, salt and temperature. Most protein aggregates can be reversed or degraded by the cell protein quality system (molecular chaperones or proteases).
However, sometimes the control mechanisms fail and accumulated aggregates transform into amyloid plaques and other protein megastructures. This is the case in protein misfolding diseases, proteopathies, such as Alzheimer’s and Parkinson’s disease. Amyloids behave very differently to functional soluble protein, for example in regards to rigidity. Current trends within this field of research is to study the kinetic buildup of such megastructures and consequently also searching for therapeutic agents that prevent buildup and hence disease. Protein misfolding diseases are a huge threat to the increasing ageing population, with such diseases affecting more than 10% of all people over the age of 65.
Learn about how aggregation of protein Tau in tauopathies, a sub-set of neurodegenerative diseases, can be studied with QCM-D.
Amyloid image source: In courtesy of Theresa Hammett and Centers for Disease Control and Prevention (http://phil.cdc.gov/phil/details.asp #10130)
Proteins tend to passively adsorb to surfaces. The amount adsorbed depends on many factors such as the protein itself, the ambient conditions and the surface material. So how can the adsorbed amount at these various conditions be assessed? Here we show how protein adsorption can be quickly measured.