...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta crystallographica. Section D, Structural biology. >Towards the spatial resolution of metalloprotein charge states by detailed modeling of XFEL crystallographic diffraction
【24h】

Towards the spatial resolution of metalloprotein charge states by detailed modeling of XFEL crystallographic diffraction

机译：对金属蛋白的空间分辨率负责国家XFEL的详细建模晶体衍射

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Oxidation states of individual metal atoms within a metalloprotein can be assigned by examining X‐ray absorption edges, which shift to higher energy for progressively more positive valence numbers. Indeed, X‐ray crystallography is well suited for such a measurement, owing to its ability to spatially resolve the scattering contributions of individual metal atoms that have distinct electronic environments contributing to protein function. However, as the magnitude of the shift is quite small, about +2?eV per valence state for iron, it has only been possible to measure the effect when performed with monochromated X‐ray sources at synchrotron facilities with energy resolutions in the range 2–3 × 10 ?4 (Δ E / E ). This paper tests whether X‐ray free‐electron laser (XFEL) pulses, which have a broader bandpass (Δ E / E = 3 × 10 ?3 ) when used without a monochromator, might also be useful for such studies. The program nanoBragg is used to simulate serial femtosecond crystallography (SFX) diffraction images with sufficient granularity to model the XFEL spectrum, the crystal mosaicity and the wavelength‐dependent anomalous scattering factors contributed by two differently charged iron centers in the 110‐amino‐acid protein, ferredoxin. Bayesian methods are then used to deduce, from the simulated data, the most likely X‐ray absorption curves for each metal atom in the protein, which agree well with the curves chosen for the simulation. The data analysis relies critically on the ability to measure the incident spectrum for each pulse, and also on the nanoBragg simulator to predict the size, shape and intensity profile of Bragg spots based on an underlying physical model that includes the absorption curves, which are then modified to produce the best agreement with the simulated data. This inference methodology potentially enables the use of SFX diffraction for the study of metalloenzyme mechanisms and, in general, offers a more detailed approach to Bragg spot data reduction.
机译：氧化态的金属原子金属蛋白可以通过检查X射线吸收应承担的边缘,转向更高能量越来越积极的价数字。适合这样的测量,由于它的空间解决散射能力单个的金属原子的贡献不同的电子环境做出贡献蛋白质的功能。这种转变是很小,+ 2呢?铁的状态,它才有可能当执行测量效果全色盲者X射线源在同步加速器设施的能量分辨率范围2 - 3×10 ? 4(ΔE / E)。X射线应承担的自由电子激光(XFEL)脉冲,应承担的有一个广泛的带通(ΔE / E = 3×10 ? 3)没有一个单色仪,使用时也可以对这些研究很有用。用于模拟连环飞秒晶体学(SFX)衍射图像足够的粒度模型XFEL谱,水晶mosaicity和波长反常散射因素的依赖由两个不同的铁中心在110年还是氨基酸应承担的蛋白质,铁氧还蛋白。推断,从模拟数据,最可能的X射线吸收曲线中每个金属原子蛋白质,与曲线吻合较好选择的模拟。极度依赖的能力来衡量的为每个脉冲入射光谱,和也nanoBragg模拟器来预测大小、形状基于布拉格和强度的点包括底层物理模型吸收曲线,然后修改与模拟产生最好的协议数据。允许使用SFX衍射研究金属酶的机制,一般来说,提供了一个更详细的布喇格点的方法数据还原。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号