1d9c
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(New page: 200px<br /><applet load="1d9c" size="450" color="white" frame="true" align="right" spinBox="true" caption="1d9c, resolution 2.0Å" /> '''BOVINE INTERFERON-GAM...)
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Revision as of 10:58, 20 November 2007
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BOVINE INTERFERON-GAMMA AT 2.0 ANGSTROMS
Overview
The structure of bovine interferon-gamma (IFN-gamma) was determined by, multiple isomorphous replacement at 2.0 A resolution. Bovine IFN-gamma, crystallizes in two related crystal forms. Crystal form 1 diffracts to 2.9, A resolution and is reproducible and stable to derivatization. Crystal, form 2 diffracts to 2.0 A resolution, but shows significant, non-isomorphism from crystal to crystal. The previously determined, structures of several different species of INF-gamma were either at too, low a resolution [human, 1hig; Ealick et al. (1991), Science, 252, 698-702] or were too inaccurate [bovine, 1rfb; Samudzi & Rubin (1993), Acta Cryst. D49(6), 505-512; rabbit, 2rig; Samudzi et al. (1991), J. Biol., Chem. 266(32), 21791-21797] for the structure to be solved by molecular, replacement. The structure was solved in crystal form 1 using two, derivatives produced by chemically modifying two free cysteine residues, that were introduced by site-directed mutagenesis (Ser30Cys, Asn59Cys)., After model building and refinement, the final R value was 21.8% (R(free), = 30.9%) for all data in the resolution range 8.0-2.9 A. The crystal form, 1 structure was then used as a molecular-replacement model for crystal, form 2 data collected from a flash-cooled crystal. Subsequent model, building and refinement, using all data in the resolution range 15.0-2.0, A, gave an R value of 19.7% and an R(free) of 27.5%. Pairwise comparison, of C(alpha) positions of bovine IFN-gamma (BOV) and the previously, determined 1rfb and 2rig structures indicated some significant differences, in the models (r.m.s.d. values for BOV to 1rfb, 4.3 A; BOV to 2rig, 4.0, A). An assessment of the quality of the structures was made using the, 3D-1D algorithm [Eisenberg et al. (1992), Faraday Discuss. 93, 25-34]. The, resulting statistical scoring indicated that BOV was consistent with, expected criteria for a 2.0 A structure, whereas both 1rfb and 2rig fell, below acceptable criteria.
About this Structure
1D9C is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
The 2.0 A structure of bovine interferon-gamma; assessment of the structural differences between species., Randal M, Kossiakoff AA, Acta Crystallogr D Biol Crystallogr. 2000 Jan;56(Pt 1):14-24. PMID:10666622
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