Crystallography: Difference between revisions

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== Understanding and extending the properties and limitations of crystallographic computations ==
== Understanding and extending the properties and limitations of crystallographic computations ==
=== Why is the final R-factor about 20% for macromolecules, but as low as 5% for small molecules? ===
 
=== Ensemble refinement, and molecular dynamics ===
# Burling et al. 1996
# Burling et al. 1996
# DePriso et al. (2004) Structure 12, 831-838
# Heterogeneity and Inaccuracy in Protein Structures Solved by X-Ray Crystallography. DePristo MA,de Bakker PIW, Blundell TL (2004) Structure 12, 831-838 [http://dx.doi.org/10.1016/j.str.2004.02.031]
# Ensemble Refinement of Protein Crystal Structures: Validation and Application. Levin EJ, Kondrashov DA, Wesenberg GE, Phillips GN, Structure 15, 1040 - 1052 [http://dx.doi.org/10.1016/j.str.2007.06.019]
# A comparison between molecular dynamics and X-ray results for dissociated CO in myoglobin. Vitkup D, Petsko GA, Karplus M. Nature Structural Biology  4, 202 - 208 (1997) [http://dx.doi.org/10.1038/nsb0397-202] (Vitkup et al showed that fitting a single model to MD-simulation derived "data" gave ~20% R, which means multiple conformers are sufficient to explain the "R-Factor Gap" between the 20% usually obtained for macromolecules, and the 5% routinely obtained for small molecules)


=== Molecular dynamics and X-ray ===  
=== Electron microscopy and X-ray ===
# A comparison between molecular dynamics and X-ray results for dissociated CO in myoglobin. Vitkup D, Petsko GA, Karplus M. Nature Structural Biology  4, 202 - 208 (1997) [http://dx.doi.org/10.1038/nsb0397-202]
# Elucidating the medium-resolution structure of ribosomal particles: an interplay between electron cryo-microscopy and X-ray crystallography. Harms J, Tocilj A, Levin I, Agmon I, Stark H, Kölln I, van Heel M, Cuff M, Schlünzen F, Bashan A, Franceschi F, Yonath A. Structure 7, 931-941 (1999) [http://dx.doi.org/10.1016/S0969-2126(99)80120-8]


=== Crystallography versus NMR ===
=== NMR versus X-ray ===
A couple of papers analysing and comparing NMR and X-ray methods/structures:
A couple of papers analysing and comparing NMR and X-ray methods/structures:
# Science (1992), vol. 257, p. 961
# Science (1992), vol. 257, p. 961
# X-ray Crystallography and NMR: Complementary Views of Structure and Dynamics, Nature Structural Biology 4, 862-865 (1997). Preprint [http://atbweb.stanford.edu/scripts/papers.php?sendfile=162 available] from Axel Brunger's "publications" website.
# X-ray Crystallography and NMR: Complementary Views of Structure and Dynamics, Nature Structural Biology 4, 862-865 (1997). Preprint [http://atbweb.stanford.edu/scripts/papers.php?sendfile=162 available] from Axel Brunger's "publications" website.
# Traditional Biomolecular Structure Determination by NMR Spectroscopy Allows for Major Errors. S.B. Nabuurs, C.A.E.M. Spronk, G.W. Vuister, G. Vriend. PLoS Comput Biol 2(2): e9. http://dx.doi.org/10.1371/journal.pcbi.0020009
# Traditional Biomolecular Structure Determination by NMR Spectroscopy Allows for Major Errors. S.B. Nabuurs, C.A.E.M. Spronk, G.W. Vuister, G. Vriend. PLoS Comput Biol 2(2): e9. http://dx.doi.org/10.1371/journal.pcbi.0020009

Revision as of 17:59, 15 November 2008

Crystallographic Theory

Crystallography Software

For Specific Tasks

Automated Pipelines for Structure Solution

Web services

Software Packages

(large packages first)

Tricks and Tips

Teaching crystallography

Understanding and extending the properties and limitations of crystallographic computations

Ensemble refinement, and molecular dynamics

  1. Burling et al. 1996
  2. Heterogeneity and Inaccuracy in Protein Structures Solved by X-Ray Crystallography. DePristo MA,de Bakker PIW, Blundell TL (2004) Structure 12, 831-838 [2]
  3. Ensemble Refinement of Protein Crystal Structures: Validation and Application. Levin EJ, Kondrashov DA, Wesenberg GE, Phillips GN, Structure 15, 1040 - 1052 [3]
  4. A comparison between molecular dynamics and X-ray results for dissociated CO in myoglobin. Vitkup D, Petsko GA, Karplus M. Nature Structural Biology 4, 202 - 208 (1997) [4] (Vitkup et al showed that fitting a single model to MD-simulation derived "data" gave ~20% R, which means multiple conformers are sufficient to explain the "R-Factor Gap" between the 20% usually obtained for macromolecules, and the 5% routinely obtained for small molecules)

Electron microscopy and X-ray

  1. Elucidating the medium-resolution structure of ribosomal particles: an interplay between electron cryo-microscopy and X-ray crystallography. Harms J, Tocilj A, Levin I, Agmon I, Stark H, Kölln I, van Heel M, Cuff M, Schlünzen F, Bashan A, Franceschi F, Yonath A. Structure 7, 931-941 (1999) [5]

NMR versus X-ray

A couple of papers analysing and comparing NMR and X-ray methods/structures:

  1. Science (1992), vol. 257, p. 961
  2. X-ray Crystallography and NMR: Complementary Views of Structure and Dynamics, Nature Structural Biology 4, 862-865 (1997). Preprint available from Axel Brunger's "publications" website.
  3. Traditional Biomolecular Structure Determination by NMR Spectroscopy Allows for Major Errors. S.B. Nabuurs, C.A.E.M. Spronk, G.W. Vuister, G. Vriend. PLoS Comput Biol 2(2): e9. http://dx.doi.org/10.1371/journal.pcbi.0020009