An upper limit for macromolecular crowding effects Public Deposited

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Creator
  • Sorrell, Courtney D
    • Other Affiliation: School of Chemistry & Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
  • Pielak, Gary J.
    • Affiliation: College of Arts and Sciences, Department of Chemistry, N.C. Cancer Hospital, UNC Lineberger Comprehensive Cancer Center, School of Medicine, Department of Biochemistry and Biophysics
  • Li, Conggang
    • Affiliation: College of Arts and Sciences, Department of Chemistry
    • Other Affiliation: State Key Laboratory of Magnetic Resonance and Molecular and Atomic Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, PR China
  • Lyon, L Andrew
    • Other Affiliation: School of Chemistry & Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
  • Miklos, Andrew C
    • Affiliation: College of Arts and Sciences, Department of Chemistry
Abstract
  • Abstract: Background: Solutions containing high macromolecule concentrations are predicted to affect a number of protein properties compared to those properties in dilute solution. In cells, these macromolecular crowders have a large range of sizes and can occupy 30% or more of the available volume. We chose to study the stability and ps-ns internal dynamics of a globular protein whose radius is ~2 nm when crowded by a synthetic microgel composed of poly(N-isopropylacrylamide-co-acrylic acid) with particle radii of ~300 nm. Results: Our studies revealed no change in protein rotational or ps-ns backbone dynamics and only mild (~0.5 kcal/mol at 37°C, pH 5.4) stabilization at a volume occupancy of 70%, which approaches the occupancy of closely packing spheres. The lack of change in rotational dynamics indicates the absence of strong crowder-protein interactions. Conclusions: Our observations are explained by the large size discrepancy between the protein and crowders and by the internal structure of the microgels, which provide interstitial spaces and internal pores where the protein can exist in a dilute solution-like environment. In summary, microgels that interact weakly with proteins do not strongly influence protein dynamics or stability because these large microgels constitute an upper size limit on crowding effects.
Date of publication
Identifier
  • doi:10.1186/2046-1682-4-13
  • 21627822
Resource type
  • Article
Rights statement
  • In Copyright
Rights holder
  • Andrew C Miklos et al.; licensee BioMed Central Ltd.
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Journal title
  • BMC Biophysics
Journal volume
  • 4
Journal issue
  • 1
Page start
  • 13
Language
  • English
Is the article or chapter peer-reviewed?
  • Yes
ISSN
  • 2046-1682
Bibliographic citation
  • BMC Biophysics. 2011 May 31;4(1):13
Access
  • Open Access
Publisher
  • BioMed Central Ltd
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