REU Project 9—Understanding the effects of molecular crowding on the structure, dynamics and stability of proteins—Dr. D. Rajalingam, Chemistry Department
A characteristic feature of the interior of cells is the total high concentration of macromolecules like lipids, sugars, and nucleic acids. Although no single macromolecule is present at high concentrations in the cell, all macromolecular species, taken together, occupy a significant fraction of the total volume of the cell medium. The accessible volume in the cell is significantly reduced and such conditions in the living cell have been termed “molecular crowding.” The steric exclusion caused by molecular crowding is expected to generate considerable energetic consequences and affect the structure, dynamics, folding, and thermodynamic properties of proteins. In general, crowding favors association reactions and affects all biochemical processes in which a change of excluded volume occurs. The effects of crowding on the reactivity of macromolecules is also implicated as one of the ways in which cells sense and respond to changes in their overall volume, induced by osmotic alterations caused by transport and metabolism. In addition, macromolecular crowding can dramatically influence the formation and accumulation of non-functional and potentially toxic aggregates within the cells. Investigation of molecular crowding on the structure, stability and dynamics of proteins is expected to provide valuable insights on the interplay of molecular forces that govern the specificity of biochemical reactions and provide useful information on the mechanisms underlying the formation of amyloid type of fibrils formed in a number of diseases, such as Alzheimer’s and Parkinson’s. In this context, we propose to investigate the effects of molecular crowding on the thermodynamic stability and dynamics of human fibroblast growth factor (FGF-expressed and purified from E. coli) using a number of biophysical techniques, including multidimensional NMR spectroscopy.