1xft
From Proteopedia
(New page: 200px<br /><applet load="1xft" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xft, resolution 3.35Å" /> '''Synchrotron X-ray Po...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1xft.gif|left|200px]]<br /><applet load="1xft" size=" | + | [[Image:1xft.gif|left|200px]]<br /><applet load="1xft" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xft, resolution 3.35Å" /> | caption="1xft, resolution 3.35Å" /> | ||
'''Synchrotron X-ray Powder Diffraction Study of Hexagonal Turkey Egg-white Lysozyme'''<br /> | '''Synchrotron X-ray Powder Diffraction Study of Hexagonal Turkey Egg-white Lysozyme'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of turkey egg-white lysozyme (TEWL) has been refined from | + | The structure of turkey egg-white lysozyme (TEWL) has been refined from high-resolution X-ray powder diffraction data. The sample was rapidly obtained as a polycrystalline precipitate at high protein concentration using 0.5 M NaCl solvent pH 6 and was deposited in the PDB with code 1xft. The diffraction data were collected at room temperature. Molecular replacement was shown to give a suitable starting point for refinement, illustrating that powder data can be sufficient for this approach. Crystallographic models were then refined by combined Rietveld and stereochemical restraint analysis of the powder data (d(min) = 3.35 A), resulting in the extraction of reliable lattice parameters and the refinement of the molecular conformation at room temperature. The structure is hexagonal [space group P6(1)22, unit-cell parameters a = 71.0862 (3), c = 85.0276 (5) A] with 12 symmetry-related molecules in the unit cell, in agreement with previous studies. The results of our analysis are indicative of specific amino acids being disordered at this temperature. Upon cooling, a sudden drop in the lattice parameters at approximately 250 K is observed concurrently with the freezing of the mother liquor. The observation of severe peak broadening below this temperature indicates strain effects accompanying the freezing transition, which are found to be reversible. Finally, a correlation between the unit-cell parameters and the pH of the buffer solution is evident, in a similar manner to earlier observations on HEWL. |
==About this Structure== | ==About this Structure== | ||
| - | 1XFT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Meleagris_gallopavo Meleagris gallopavo]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http:// | + | 1XFT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Meleagris_gallopavo Meleagris gallopavo]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XFT OCA]. |
==Reference== | ==Reference== | ||
| Line 15: | Line 15: | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Margiolaki, I.]] | [[Category: Margiolaki, I.]] | ||
| - | [[Category: Wright, J | + | [[Category: Wright, J P.]] |
[[Category: lysozyme]] | [[Category: lysozyme]] | ||
[[Category: powder diffraction]] | [[Category: powder diffraction]] | ||
[[Category: x-rays]] | [[Category: x-rays]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:54:19 2008'' |
Revision as of 13:54, 21 February 2008
|
Synchrotron X-ray Powder Diffraction Study of Hexagonal Turkey Egg-white Lysozyme
Overview
The structure of turkey egg-white lysozyme (TEWL) has been refined from high-resolution X-ray powder diffraction data. The sample was rapidly obtained as a polycrystalline precipitate at high protein concentration using 0.5 M NaCl solvent pH 6 and was deposited in the PDB with code 1xft. The diffraction data were collected at room temperature. Molecular replacement was shown to give a suitable starting point for refinement, illustrating that powder data can be sufficient for this approach. Crystallographic models were then refined by combined Rietveld and stereochemical restraint analysis of the powder data (d(min) = 3.35 A), resulting in the extraction of reliable lattice parameters and the refinement of the molecular conformation at room temperature. The structure is hexagonal [space group P6(1)22, unit-cell parameters a = 71.0862 (3), c = 85.0276 (5) A] with 12 symmetry-related molecules in the unit cell, in agreement with previous studies. The results of our analysis are indicative of specific amino acids being disordered at this temperature. Upon cooling, a sudden drop in the lattice parameters at approximately 250 K is observed concurrently with the freezing of the mother liquor. The observation of severe peak broadening below this temperature indicates strain effects accompanying the freezing transition, which are found to be reversible. Finally, a correlation between the unit-cell parameters and the pH of the buffer solution is evident, in a similar manner to earlier observations on HEWL.
About this Structure
1XFT is a Single protein structure of sequence from Meleagris gallopavo. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
Reference
Synchrotron X-ray powder diffraction study of hexagonal turkey egg-white lysozyme., Margiolaki I, Wright JP, Fitch AN, Fox GC, Von Dreele RB, Acta Crystallogr D Biol Crystallogr. 2005 Apr;61(Pt 4):423-32. Epub 2005, Mar 24. PMID:15805597
Page seeded by OCA on Thu Feb 21 15:54:19 2008
