Structural biology: Molecular machinery in action
 

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Nature 445, 609 (8 February 2007) | <abbr title="Digital Object Identifier">doi</abbr>:10.1038/nature05566; Published online 21 January 2007

Structural biology: Molecular machinery in action

Ad Bax and Dennis A. Torchia

Abstract

Nuclear magnetic resonance is the best way to study motion in proteins, but it could be applied only to small systems. This limitation has been overcome to reveal the dynamics of a large protein complex.



THE ORIGINAL PAPER is here!!



Nature 445, 618-622 (8 February 2007) | <abbr title="Digital Object Identifier">doi</abbr>:10.1038/nature05512; Received 28 July 2006; Accepted 6 December 2006; Published online 21 January 2007

Quantitative dynamics and binding studies of the 20S proteasome by NMR

Remco Sprangers and Lewis E. Kay

http://www.nature.com/nature/journal...e05512_F1.htmlFigure


Departments of Biochemistry, Medical Genetics and Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada

Abstract

The machinery used by the cell to perform essential biological processes is made up of large molecular assemblies. One such complex, the proteasome, is the central molecular machine for removal of damaged and misfolded proteins from the cell. Here we show that for the 670-kilodalton 20S proteasome core particle it is possible to overcome the molecular weight limitations that have traditionally hampered quantitative nuclear magnetic resonance (NMR) spectroscopy studies of such large systems. This is achieved by using an isotope labelling scheme where isoleucine, leucine and valine methyls are protonated in an otherwise highly deuterated background in concert with experiments that preserve the lifetimes of the resulting NMR signals. The methodology has been applied to the 20S core particle to reveal functionally important motions and interactions by recording spectra on complexes with molecular weights of up to a megadalton. Our results establish that NMR spectroscopy can provide detailed insight into supra-molecular structures over an order of magnitude larger than those routinely studied using methodology that is generally applicable.