Molten Globule in the Microgravity: Role of Gravity on Protein Folding Process

Nowadays, the biological effects of microgravity have been the subject of various experimental researches. The purpose of this study was to investigate the probable biological effects of microgravity on the human serum albumin (HSA) structure after 3 and 24 h exposure via various spectroscopic instruments. The UV-Visible, near-UV-CD and intrinsic fluorescence spectroscopy represented that microgravity can remarkably change the tertiary structure of HSA. Additionally, the ANS affinity for HSA incremented when the protein was exposed to simulate microgravity compared to unexposed HSA, which may possibly have appeared attributable to expansion of the structure of simulated HSA. Fluorescence quenching by acrylamide demonstrated higher stern–volmer constant for exposed HSA. The results of zeta potential and dynamic light scattering (DLS) experiments depicted that simulated microgravity cause raise in the surface charge and size of HSA. Far-UV CD data demonstrated that simulated microgravity did not perturb the secondary structures of the protein. Collectively, our results suggest that HSA after 24 h exposure to microgravity can exhibit a molten globule (MG) structure. This is the first report to demonstrate the molten globule state formation in microgravity condition. Results from this study could give knowledge to understand the role of gravity on protein folding process. In addition, this finding could help to find out safe limits for astronauts and space travelers and to develop adequate countermeasures against any harmful effects of microgravity.

کلیدواژه ها:

Microgravity ، Human Serum Albumin (HSA) ، Molten Globule (MG) ، Spectroscopic Instruments ، Clinostat