Effects of macromolecular crowding on the structure of a protein complex: A small-angle scattering study of superoxide dismutase

Ajith Rajapaksha, Christopher B. Stanley, Brian A. Todd

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

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 languageEnglish
Pages (from-to)967-974
Number of pages8
JournalBiophysical Journal
Volume108
Issue number4
DOIs
StatePublished - 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.

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