NMR Ensembles of Models: Difference between revisions
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About 14% of the entries in the [[Protein Data Bank]] were determined by nuclear magnetic resonance in solution (NMR) as of mid-2008. 85% were determined by X-ray crystallography, and <1% by other methods. NMR can only be used for relatively small macromolecules (see [[#Median_Size_of_Published_NMR_Structures|below]]). | About 14% of the entries in the [[Protein Data Bank]] were determined by nuclear magnetic resonance in solution (NMR) as of mid-2008. 85% were determined by X-ray crystallography, and <1% by other methods. NMR can only be used for relatively small macromolecules (see [[#Median_Size_of_Published_NMR_Structures|below]]). | ||
NMR measurements yield a set of interatomic distances, called "restraints". Model building for NMR experiments typically starts with the complete protein or nucleic acid chain, including [[Hydrogen|hydrogen atoms]]. The distance restraints are then applied. The resulting model usually includes the entire protein and nucleic acid chains, unlike [[X-ray crystallography|X-ray crystallographic]] models that often lack the ends, and even loops in the middle of chains, due to [[Disorder]] in protein crystals. | NMR measurements yield a set of interatomic distances, called "restraints". Model building for NMR experiments typically starts with the complete protein or nucleic acid chain, including [[Hydrogen in macromolecular models|hydrogen atoms]]. The distance restraints are then applied. The resulting model usually includes the entire protein and nucleic acid chains, unlike [[X-ray crystallography|X-ray crystallographic]] models that often lack the ends, and even loops in the middle of chains, due to [[Disorder|disorder]] in protein crystals. | ||
Macromolecular structure determination by NMR is done in aqueous solution, and thus requires that the molecule be soluble. For more information, see ''Nature of 3D Structural Data''<ref>[http://www.pdb.org/pdb/static.do?p=general_information/about_pdb/nature_of_3d_structural_data.html Nature of 3D Structural Data]</ref> and ''NMR in Wikipedia''<ref>[http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance NMR in Wikipedia]</ref>. | Macromolecular structure determination by NMR is done in aqueous solution, and thus requires that the molecule be soluble. For more information, see ''Nature of 3D Structural Data''<ref>[http://www.pdb.org/pdb/static.do?p=general_information/about_pdb/nature_of_3d_structural_data.html Nature of 3D Structural Data]</ref> and ''NMR in Wikipedia''<ref>[http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance NMR in Wikipedia]</ref>. | ||