Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis.
Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis.
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DOI：
10.1007/978-1-4939-7000-1_16
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Hendrickson WA
中科院分区：
文献类型：
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作者：
Liu Q;Hendrickson WA
正常的弹性X射线散射，只取决于电子密度，可以调制的“异常”组件，由于X射线和电子轨道之间的共振。反常散射从而精确地识别原子种类，因为轨道区分原子元素，这使得多波长和单波长反常衍射（MAD和SAD）方法成为可能。SAD现在占主导地位的从头结构测定的生物大分子，我们在这里集中在流行的SAD方法。我们描述的异常相位理论和周期表的相位元素，可用于SAD实验，区分那些容易获得的共振实验和那些可以有效地远离边缘。我们描述了目前的SAD定相实验的程序，我们讨论了具有挑战性的应用程序的异常信号的优化。我们还描述了使用异常信号作为示踪和元素鉴定的分子标记的方法。简要讨论了新出现的事态发展和前景。
The normal elastic X-ray scattering that depends only on electron density can be modulated by an ‘anomalous’ component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those that can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.