Structural, Functional, and Dynamical Responses of a Protein in a Restricted Environment Imposed by Macromolecular Crowding.

The intercellular environment is known to be very different from the environment where most of the elementary biological processes are studied in the laboratory. As a result, there was a considerable effort on cell mimicking either by confinement or by introducing macromolecular crowding. In the present study, dextran of varying sizes has been used to crowd the environment of a protein, human serum albumin (HSA), and its structure, dynamics, and activity were studied as a function of crowder concentration. By employing bulk and single molecular level spectroscopic measurements, we elucidate the overall structure and local microsecond dynamics of HSA. Further, we have attempted to correlate these structural changes with its activity.