2ybm
Nitrate X-ray induced reduction on HEWL crystals (23.3 MGy)
Structural highlights
FunctionLYSC_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.[1] Publication Abstract from PubMedThe rate of radiation damage to macromolecular crystals at both room temperature and 100 K has previously been shown to be reduced by the use of certain radical scavengers. Here the effects of sodium nitrate, an electron scavenger, are investigated at 100 K. For sodium nitrate at a concentration of 0.5 M in chicken egg-white lysozyme crystals, the dose tolerance is increased by a factor of two as judged from the global damage parameters, and no specific structural damage to the disulfide bonds is seen until the dose is greatly in excess (more than a factor of five) of the value at which damage appears in electron density maps derived from a scavenger-free crystal. In the electron density maps, ordered nitrate ions adjacent to the disulfide bonds are seen to lose an O atom, and appear to protect the disulfide bonds. In addition, results reinforcing previous reports on the effectiveness of ascorbate are presented. The mechanisms of action of both scavengers in the crystalline environment are elucidated. Effective scavenging at cryotemperatures: further increasing the dose tolerance of protein crystals.,De la Mora E, Carmichael I, Garman EF J Synchrotron Radiat. 2011 May;18(Pt 3):346-57. Epub 2011 Apr 1. PMID:21525642[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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