2id8: Difference between revisions

[[Image:2id8.gif|left|200px]]<br /><applet load="2id8" size="350" color="white" frame="true" align="right" spinBox="true"  

X-ray single-wavelength anomalous diffraction (SAD) data from a crystal of proteinase K were collected using synchrotron radiation of 0.98 A wavelength at SER-CAT 22-ID beamline, Advanced Photon Source, Argonne National Laboratory. At this wavelength, the expected Bijvoet ratio resulting from the presence of one calcium, one chloride and ten S atoms in the 279-residue protein is extremely small at approximately 0.46%. The direct-methods program SHELXD located 11 anomalous sites using data truncated to 2 A resolution. SHELXE was used to produce an easily interpretable electron-density map. This study shows that an accurate beamline and a good-quality crystal provide the possibility of successfully using a very weak anomalous signal of sulfur measured at a short wavelength for phasing a protein structure, even if a small degree of radiation damage is present.

2ID8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Engyodontium_album Engyodontium album] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=NO3:'>NO3</scene>, <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=2DB:'>2DB</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Peptidase_K Peptidase K], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.64 3.4.21.64] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ID8 OCA].  

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:51:27 2008''