NMR Ensembles of Models: Difference between revisions
Eric Martz (talk | contribs) →NMR Experiments Yield Multiple Models: adding content |
Eric Martz (talk | contribs) →NMR Experiments Yield Multiple Models: adding content |
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When a macromolecular structure is determined by nuclear magnetic resonance (NMR) in solution, the result is an '''ensemble of multiple molecular models''', each of which is consistent with the experimental data. The results of an NMR experiment are a large number of inter-atomic distance restraints, which are consistent with multiple models. This is in contrast to the result of an X-ray crystallographic experiment, which is a single model that best fits the empirical electron density. (In some cases where the resolution is very high, the model may include alternative positions for some atoms.) | When a macromolecular structure is determined by nuclear magnetic resonance (NMR) in solution, the result is an '''ensemble of multiple molecular models''', each of which is consistent with the experimental data. The results of an NMR experiment are a large number of inter-atomic distance restraints, which are consistent with multiple models. This is in contrast to the result of an X-ray crystallographic experiment, which is a single model that best fits the empirical electron density. (In some cases where the resolution is very high, the model may include alternative positions for some atoms.) | ||
The number of NMR models published depends upon the experiment and is up to the authors, and varies between 2 (e.g. [[1cvo]]) and over 100. The first model in the ensemble has no special significance (see [[#The Most Representative Model|the most representative model]]). | The number of NMR models published depends upon the experiment and is up to the authors, and varies between 2 (e.g. [[1cvo]]) and over 100. The median number of models is 20. (You can search for entries with a specified number or range of models using [[User:OCA|OCA]]). The first model in the ensemble has no special significance (see [[#The Most Representative Model|the most representative model]]). | ||
===Meaning of the Variation Between Models=== | ===Meaning of the Variation Between Models=== | ||