Site-Directed Methyl Group Labeling as an NMR Probe of Structure and Dynamics in Supra-Molecular Protein Systems: Applications to the Proteasome and to the ClpP Protease.

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Site-Directed Methyl Group Labeling as an NMR Probe of Structure and Dynamics in Supra-Molecular Protein Systems: Applications to the Proteasome and to the ClpP Protease.

Site-Directed Methyl Group Labeling as an NMR Probe of Structure and Dynamics in Supra-Molecular Protein Systems: Applications to the Proteasome and to the ClpP Protease.

J Am Chem Soc. 2011 May 11;

Authors: Religa TL, Ruschak AM, Rosenzweig R, Kay LE

Methyl groups are powerful reporters of structure, motion and function in NMR studies of supra-molecular protein assemblies. Their utility can be hindered, however, by spectral overlap, difficulties with assignment or lack of probes in biologically important regions of the molecule studied. Here we show that 13CH3-S- labeling of Cys side-chains using 13C-methyl-methanethiosulfonate (13C-MMTS) (IUPAC name: methylsulfonylsulfanylmethane) provides a convenient probe of molecular structure and dynamics. The methodology is demonstrated with an application focusing on the gating residues of the T. acidophilum proteasome, where it is shown that the 13CH3-S- label reports faithfully on the conformational heterogeneity and dynamics in this region of the complex. A second and related application involves labeling with 13C-MMTS at the N-termini of the subunits comprising the E. coli ClpP protease that reveals multiple conformations of gating residues in this complex as well. These N-terminal residues adopt a single conformation upon gate opening.

PMID: 21557628 [PubMed - as supplied by publisher]



Source: PubMed