title: Reconstruction of the three-dimensional NMR spectrum of a protein from a set of plane projections.
abstract: Three-dimensional protein NMR spectra can be obtained significantly faster than by traditional methods by a projection-reconstruction procedure related to X-ray tomography. First, two orthogonal projections are acquired in quick two-dimensional experiments with the evolution parameters t(1) or t(2) set to zero. These projections define a three-dimensional lattice; all cross-peaks must lie on this lattice but not all lattice points are occupied. A third experiment with t(1) and t(2) incremented simultaneously and in a fixed ratio, generates a projection onto a tilted plane and thus establishes the positions of all the cross-peaks unambiguously. This projection-reconstruction technique has been tested on the 500 MHz three-dimensional HNCO spectrum of ubiquitin.
mesh_terms: D021621:Imaging, Three-Dimensional; D008962:Models, Theoretical; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D011506:Proteins; D025801:Ubiquitin