2anx
|
crystal structure of bacteriophage P22 lysozyme mutant L87M
OverviewOverview
The X-ray crystal structure of the previously unknown bacteriophage P22, lysozyme, the product of gene 19, has been determined ab initio by direct, methods using the program SIR2002. The presence of several partially, occupied iodine anions and samarium cations augmented the ability of, direct methods to locate all 2268 non-H protein atoms in the asymmetric, unit, making this one of the largest structures to date to be determined, ab initio. The iodides were introduced from a quick soak, which the, crystal survived sufficiently well to diffract to 1.04 angstroms, resolution. The complete heavy-atom substructure contributed 6.6% of the, total scattering power. The initial determination of the structure assumed, that there were two iodide ions in the asymmetric unit, although it was, later determined that these sites correspond to partially occupied, samarium ions. Tests suggested that it is better to overestimate rather, than underestimate the heavy-atom content. While experimental phases from, all of the successful tests were of high quality, the best results came, from a SAD experiment using the programs SHELXD and SHELXE. Nonetheless, ab initio structure determination by direct methods was found to be a, viable alternative to traditional protein crystallographic methods, provided that the X-ray data extend to atomic resolution and heavy atoms, with sufficient scattering power are present in the crystal.
About this StructureAbout this Structure
2ANX is a Single protein structure of sequence from Yersinia phage py54 with SO4, SM, IOD and MG as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
Extension to 2268 atoms of direct methods in the ab initio determination of the unknown structure of bacteriophage P22 lysozyme., Mooers BH, Matthews BW, Acta Crystallogr D Biol Crystallogr. 2006 Feb;62(Pt 2):165-76. Epub 2006, Jan 18. PMID:16421448
Page seeded by OCA on Wed Nov 21 08:15:12 2007