晶体孪晶
结晶学
结晶
Crystal(编程语言)
同步辐射
晶体结构
材料科学
化学
物理
光学
计算机科学
微观结构
有机化学
程序设计语言
作者
Carlos Contreras-Martel,José Martínez-Oyanedel,Marta Bunster,Pierre Legrand,Claudine Piras,X. Vernede,Juan C. Fontecilla-Camps
出处
期刊:Acta Crystallographica Section D-biological Crystallography
[International Union of Crystallography]
日期:2001-01-01
卷期号:57 (1): 52-60
被引量:46
标识
DOI:10.1107/s0907444900015274
摘要
R-phycoerythrin, a light-harvesting component from the red algae Gracilaria chilensis, was crystallized by vapour diffusion using ammonium sulfate as precipitant agent. Red crystals grew after one week at 293 K and diffracted to 2.70 A resolution. Three serial macroseeding assays were necessary to grow a second larger crystal to dimensions of 0.68 x 0.16 x 0.16 mm. This crystal diffracted to 2.24 A resolution using synchrotron radiation at beamline BM14 of the European Synchrotron Radiation Facility (ESRF) at Grenoble, France and was used for structure determination. Data were collected at 100 K to a completeness of 98.6%. The crystal was trigonal, space group R3, with unit-cell parameters a = b = 187.3, c = 59.1 A, alpha = beta = 90, gamma = 120 degrees. Data treatment using the CCP4 suite of programs indicated that the crystal was twinned ((I(2))/(I)(2) = 1.41). Molecular replacement was performed with AMoRe using the R-phycoerythrin from Polysiphonia urceolata [Chang et al. (1996), J. Mol. Biol. 249, 424-440] as a search model. In order to overcome the twinning problem, SHELX97 was used for the crystallographic refinement. The twin fraction was 0.48, indicating a nearly perfect hemihedrally twinned crystal. The final R(work) and R(free) factors are 0.16 and 0.25, respectively. All the residues and chromophores of the alpha- and beta-chains are well defined in the electron-density maps. Some residues belonging to the gamma-linker are also recognizable.
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