Differential Dynamical Effects of Macromolecular Crowding on an Intrinsically Disordered Protein and a Globular Protein: Implications for In-Cell NMR Spectroscopy

J. Am. Chem. Soc., 130 (20), 6310–6311, 2008. 10.1021/ja801020z
Web Release Date: April 18, 2008

Differential Dynamical Effects of Macromolecular Crowding on an Intrinsically Disordered Protein and a Globular Protein: Implications for In-Cell NMR Spectroscopy

Conggang Li,^† Lisa M. Charlton,^† Asha Lakkavaram,^† Christopher Seagle,^‡ Guifang Wang,^† Gregory B. Young,^§ Jeffrey M. Macdonald,^‡ and Gary J. Pielak^*^†^§^∥

Department of Chemistry, Department of Biomedical Engineering, Department of Biochemistry and Biophysics, and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599

gary_pielak@unc.edu

Received February 9, 2008

Abstract:

In-cell NMR provides a valuable means to assess how macromolecules, with concentrations up to 300 g/L in the cytoplasm, affect the structure and dynamics of proteins at atomic resolution. Here an intrinsically disordered protein, α-synuclein (αSN), and a globular protein, chymotrypsin inhibitor 2 (CI2) were examined by using in-cell NMR. High-resolution in-cell spectra of αSN can be obtained, but CI2 leaks from the cell and the remaining intracellular CI2 is not detectable. Even after stabilizing the cells from leakage by using alginate encapsulation, no CI2 signal is detected. From in vitro studies we conclude that this difference in detectability is the result of the differential dynamical response of disordered and ordered proteins to the changes of motion caused by the increased viscosity in cells.

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