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Tryparedoxin II from C.fasciculata solved by sulphur phasing
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe de novo phasing of the structures of two crystal forms of tryparedoxin II from Crithidia fasciculata has been carried out using single-wavelength anomalous diffraction techniques exploiting only the small anomalous signal from the S atoms intrinsic to the native protein. Data were collected at 1.77 A wavelength, where the Bijvoet ratio is approximately 1.2%. Data collected to d(min) = 2.5 A from a crystal of form I, which has a diffraction limit of d(min) = 1.5 A and a solvent content of approximately 46%, produced readily interpretable electron-density maps. When these phases were extended to the resolution limit of the crystals, almost the entire model could be traced automatically. Crystals of form II have a much higher solvent content, approximately 72%, and a much lower diffraction limit than form I and at 1.77 A wavelength yielded data only to d(min) = 2.7 A. Despite the medium resolution of the data for this crystal form, it was possible both to determine the heavy-atom partial structure and then use it to produce, still at d(min) = 2.7 A, an excellent quality interpretable electron-density map. This was then improved by phase extension to the d(min) = 2.35 A diffraction limits of a different crystal for which data were collected on a more intense beamline. The success of this latter structure solution markedly increases the potential use in macromolecular crystal structure determination of the anomalous signal available from S atoms that occur naturally in proteins and, as is discussed, has significant implications for structure determination in the high-throughput era. De novo phasing of two crystal forms of tryparedoxin II using the anomalous scattering from S atoms: a combination of small signal and medium resolution reveals this to be a general tool for solving protein crystal structures.,Micossi E, Hunter WN, Leonard GA Acta Crystallogr D Biol Crystallogr. 2002 Jan;58(Pt 1):21-8. Epub 2001 Dec, 21. PMID:11752776[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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