Effects of Macromolecular Crowding on the Structure of a Protein Complex: A Small-Angle Scattering Study of Superoxide Dismutase

Journal Article · Sun Feb 01 00:00:00 EST 2015 · Biophysical Journal

DOI:https://doi.org/10.1016/j.bpj.2014.12.046· OSTI ID:1233994

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

Macromolecular crowding can alter the structure and function of biological macromolecules. We used small angle scattering (SAS) to measure the change in size of a protein complex, superoxide dismutase (SOD), induced by macromolecular crowding. Crowding was induced using 400 MW polyethylene glycol (PEG), triethylene glycol (TEG), methyl- -glucoside ( -MG) and trimethylamine N-oxide (TMAO). Parallel small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) 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. SAXS done in the presence of TEG suggests that for further deformation beyond a 9% decrease in volume the resistance to deformation may increase dramatically.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1233994
• Alternate ID(s): OSTI ID: 1185824
• Journal Information: Biophysical Journal, Journal Name: Biophysical Journal Vol. 108 Journal Issue: 4; ISSN 0006-3495
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES