Molecular crowding effects on the internal dynamics of proteins

In living cells, the molecular crowding is a routinely occurring condition with concentrations of macromolecules reaching up to 300-400 mg/ml. Such high concentrations can easily alter the behavior and the properties of the proteins in the cytosol. Molecular crowding may affect enzyme reactions if the reaction requires a large change in the shape of the enzyme and may be of key importance in transcription and DNA replication by increasing the strength of interactions between proteins and DNA . The importance of crowding in protein folding is of particular interest in biophysics. Crowded protein environments have both, positive and negatives outcomes like accelerate the folding process, since a compact folded protein will occupy less volume than an unfolded protein chain; reduce the yield of correctly folded proteins; increase protein aggregation by misfolding and increase the effectiveness of chaperone proteins in the cell which could counteract the reduction in folding efficiency.

Here, I use neutrons to show how macromolecular crowding affects several human body protein dynamics as well as the overall proteins shape, where distinct conformational changes are accompanied by secondary structure alterations implying that crowding-induced shape changes may be important for the protein function and malfunction in vivo.