title: Breaking symmetry in the structure determination of (large) symmetric protein dimers.
abstract: We demonstrate a novel methodology to disrupt the symmetry in the NMR spectra of homodimers. A paramagnetic probe is introduced sub-stoichiometrically to create an asymmetric system with the paramagnetic probe residing on only one monomer within the dimer. This creates sufficient magnetic anisotropy for resolution of symmetry-related overlapped resonances and, consequently, detection of pseudocontact shifts and residual dipolar couplings specific to each monomeric component. These pseudocontact shifts can be readily incorporated into existing structure refinement calculations and enable determination of monomer orientation within the dimeric protein. This methodology can be widely used for solution structure determination of symmetric dimers.
authors.affiliation: Structural Biophysics Laboratory, National Cancer Institute, PO Box B, Frederick, MD 21702-1201, USA.
authors.forename: Vadim
authors.initials: V
authors.lastname: Gaponenko
authors.forename: Amanda S
authors.initials: AS
authors.lastname: Altieri
authors.forename: Jess
authors.initials: J
authors.lastname: Li
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Byrd
mesh_terms: D004268:DNA-Binding Proteins / Q000737:chemistry; D019281:Dimerization; D004492:Edetic Acid / Q000737:chemistry; D046911:Macromolecular Substances; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D050797:STAT4 Transcription Factor; D015534:Trans-Activators / Q000737:chemistry
chemical_list: D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D011506:Proteins; D050797:STAT4 Transcription Factor; D015534:Trans-Activators; D004492:Edetic Acid