1sx7: Difference between revisions
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[[Image:1sx7.jpg|left|200px]] | [[Image:1sx7.jpg|left|200px]] | ||
'''Use of an ion-binding site to bypass the 1000-atom limit to ab initio structure determination by direct methods''' | {{Structure | ||
|PDB= 1sx7 |SIZE=350|CAPTION= <scene name='initialview01'>1sx7</scene>, resolution 1.06Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=RB:RUBIDIUM+ION'>RB</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene> and <scene name='pdbligand=BME:BETA-MERCAPTOETHANOL'>BME</scene> | |||
|ACTIVITY= [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] | |||
|GENE= E ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id= Bacteriophage T4]) | |||
}} | |||
'''Use of an ion-binding site to bypass the 1000-atom limit to ab initio structure determination by direct methods''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1SX7 is a [ | 1SX7 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SX7 OCA]. | ||
==Reference== | ==Reference== | ||
Use of an ion-binding site to bypass the 1000-atom limit to structure determination by direct methods., Mooers BH, Matthews BW, Acta Crystallogr D Biol Crystallogr. 2004 Oct;60(Pt 10):1726-37. Epub 2004, Sep 23. PMID:[http:// | Use of an ion-binding site to bypass the 1000-atom limit to structure determination by direct methods., Mooers BH, Matthews BW, Acta Crystallogr D Biol Crystallogr. 2004 Oct;60(Pt 10):1726-37. Epub 2004, Sep 23. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15388918 15388918] | ||
[[Category: Bacteriophage t4]] | [[Category: Bacteriophage t4]] | ||
[[Category: Lysozyme]] | [[Category: Lysozyme]] | ||
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[[Category: CL]] | [[Category: CL]] | ||
[[Category: RB]] | [[Category: RB]] | ||
[[Category: ab initio direct | [[Category: ab initio direct method]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 14:10:50 2008'' | ||
Revision as of 12:10, 20 March 2008
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| 1sx7, resolution 1.06Å | |||||||||||||
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| Ligands: | RB, CL and BME | ||||||||||||
| Gene: | E (Bacteriophage T4) | ||||||||||||
| Activity: | Lysozyme, with EC number 3.2.1.17 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Use of an ion-binding site to bypass the 1000-atom limit to ab initio structure determination by direct methods
Overview
Proteins with more than 1000 non-H atoms and without heavy-atom prosthetic groups are very difficult to solve by ab initio direct methods. T4 lysozyme is being used to explore these limits. The protein has 1309 non-H atoms, seven S atoms, no disulfide bonds and no heavy-atom prosthetic group. It is recalcitrant to structure determination by direct methods using X-ray diffraction data to 0.97 A. It is shown here that it is possible to obtain a truly ab initio structure determination of a variant of the protein that has an Rb+ (Z = 37) binding site. Using diffraction data to 1.06 A resolution, the direct-methods programs SIR2002 and ACORN independently solved the structure in about 20 h. The bound Rb+, which contributes about 1.7% of the total scattering, does not appear to distort the structure or to inhibit refinement (R factor 12.1%). The phases obtained via SIR2002 or ACORN are in good agreement with those from a reference structure obtained from conventional molecular-substitution and refinement procedures (average error in the figure-of-merit-weighted phases of less than 25 degrees). Thus, proteins with more than 1000 atoms that include halide-binding or other such sites may be amenable to structure determination by ab initio direct methods. The direct-methods approaches are also compared with structure determination via use of the anomalous scattering of the Rb+ ion. As shown by examples, high-resolution structures determined by direct methods can be useful in highlighting regions of strain in the protein, including short hydrogen bonds and non-planar peptide groups.
About this Structure
1SX7 is a Single protein structure of sequence from Bacteriophage t4. Full crystallographic information is available from OCA.
Reference
Use of an ion-binding site to bypass the 1000-atom limit to structure determination by direct methods., Mooers BH, Matthews BW, Acta Crystallogr D Biol Crystallogr. 2004 Oct;60(Pt 10):1726-37. Epub 2004, Sep 23. PMID:15388918
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