Sammanfattning
Transverse relaxation dispersion NMR spectroscopy can provide atom-specific information about time scales, populations, and the extent of structural reorganization in proteins under equilibrium conditions. A method is described that uses side-chain methyl groups as local reporters for conformational transitions taking place in the microsecond regime. The experiment measures carbon nuclear spin relaxation rates in the presence of continuous wave off-resonance irradiation, in proteins uniformly enriched with C-13, and partially randomly labeled with 2 H. The method was applied to human FK-506 binding protein (FKBP12), which uses a common surface for binding substrates in its dual role as both an immunophilin and folding assistant. Conformational dynamics on a time scale of similar to 130 mu s were detected for methyl groups located in the substrate binding pocket, demonstrating its plasticity in the absence of substrate. The spatial arrangement of affected side-chain atoms suggests that substrate recognition involves the rapid relative movement of the subdomain comprising residues Ala81-Thr96 and that the observed dynamics play an important role in facilitating the interaction of this protein with its many partners, including calcineurin.
Originalspråk | engelska |
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Sidor (från-till) | 5718-5727 |
Tidskrift | Journal of the American Chemical Society |
Volym | 128 |
Nummer | 17 |
DOI | |
Status | Published - 2006 |
Ämnesklassifikation (UKÄ)
- Fysikalisk kemi