Abstract
Macromolecular crowding can alter the structure and function of biological macromolecules. We used small-angle scattering to measure the effects of macromolecular crowding on the size of a protein complex, SOD (superoxide dismutase). Crowding was induced using 400 MW PEG (polyethylene glycol),TEG (triethylene glycol), α-MG (methyl-α-glucoside), and TMAO (trimethylamine n-oxide). Parallel small-angle neutron scattering and small-angle x-ray scattering allowed us to unambiguously attribute apparent changes in radius of gyration to changes in the structure of SOD. For a 40% PEG solution, we find that the volume of SOD was reduced by 9%. Considering the osmotic pressure due to PEG, this deformation corresponds to a highly compressible structure. Small-angle x-ray scattering done in the presence of TEG suggests that for further deformation - beyond a 9% decrease in volume - the resistance to deformation may increase dramatically.
Original language | English |
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Pages (from-to) | 967-974 |
Number of pages | 8 |
Journal | Biophysical Journal |
Volume | 108 |
Issue number | 4 |
DOIs | |
State | Published - Feb 17 2015 |
Funding
The research was supported by the National Science Foundation (grant No. 1006485-DMR). A portion of the research performed at Oak Ridge National Laboratory’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.