4htk | pdb_00004htk

Mitigation of X-ray damage in macromolecular crystallography by submicrometer line focusing; total dose 2.17 x 10e+12 X-ray photons

spinqualitylabelsall models 4htk, resolution 1.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4htk is a 1 chain structure with sequence from Gallus gallus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.2Å Ligands: CL, EDO, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function LYSC_CHICK Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Has bacteriolytic activity against M.luteus. Publication Abstract from PubMed Reported here are measurements of the penetration depth and spatial distribution of photoelectron (PE) damage excited by 18.6 keV X-ray photons in a lysozyme crystal with a vertical submicrometre line-focus beam of 0.7 microm full-width half-maximum (FWHM). The experimental results determined that the penetration depth of PEs is 5 +/- 0.5 microm with a monotonically decreasing spatial distribution shape, resulting in mitigation of diffraction signal damage. This does not agree with previous theoretical predication that the mitigation of damage requires a peak of damage outside the focus. A new improved calculation provides some qualitative agreement with the experimental results, but significant errors still remain. The mitigation of radiation damage by line focusing was measured experimentally by comparing the damage in the X-ray-irradiated regions of the submicrometre focus with the large-beam case under conditions of equal exposure and equal volumes of the protein crystal, and a mitigation factor of 4.4 +/- 0.4 was determined. The mitigation of radiation damage is caused by spatial separation of the dominant PE radiation-damage component from the crystal region of the line-focus beam that contributes the diffraction signal. The diffraction signal is generated by coherent scattering of incident X-rays (which introduces no damage), while the overwhelming proportion of damage is caused by PE emission as X-ray photons are absorbed. Mitigation of X-ray damage in macromolecular crystallography by submicrometre line focusing.,Finfrock YZ, Stern EA, Alkire RW, Kas JJ, Evans-Lutterodt K, Stein A, Duke N, Lazarski K, Joachimiak A Acta Crystallogr D Biol Crystallogr. 2013 Aug;69(Pt 8):1463-9. doi:, 10.1107/S0907444913009335. Epub 2013 Jul 17. PMID:23897469 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lysozyme 3D structures

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