5tmc

Re-refinement of Thermus thermopiles DNA-directed RNA polymerase structure

spinqualitylabelsall models 5tmc, resolution 2.71Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5tmc is a 7 chain structure with sequence from Thermus thermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.71Å Ligands: G4P, MG, PO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RPOA_THET8 DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Publication Abstract from PubMed In 2008, Zwart and colleagues observed that the fraction of the structures deposited in the PDB alleged to have "pseudosymmetry" or "special noncrystallographic symmetry" (NCS) was about 6%, and that this percentage was rising annually. A few years later, Poon and colleagues found that 2% of all the crystal structures in the PDB belonged to higher symmetry space groups than those assigned to them. Here, I report an analysis of the X-ray diffraction data deposited for this class of structures, which shows that most of the "pseudosymmetry" and "special NCS" that has been reported is in fact true crystallographic symmetry (CS). This distinction is important because the credibility of crystal structures depends heavily on quality control statistics such as Rfree that are unreliable when they are computed incorrectly, which they often are when CS is misidentified as "special NCS" or "pseudosymmetry". When mistakes of this kind are made, artificially low values of Rfree can give unjustified confidence in the accuracy of the reported structures. On the validation of crystallographic symmetry and the quality of structures.,Wang J Protein Sci. 2015 May;24(5):621-32. doi: 10.1002/pro.2595. Epub 2014 Dec 9. PMID:25352397 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RNA polymerase 3D structures Sigma factor 3D structures

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