蛋白质氨基酸的综合实验与理论光谱研究
A Comprehensive Experimental and Theoretical Spectroscopic Study of Proteinogenic Amino Acids
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中文总结 AI 辅助
该研究针对固态氨基酸化学和电子结构了解有限的问题，结合X射线光电子能谱与密度泛函理论计算，系统研究20种蛋白质氨基酸及硒代蛋氨酸相关状态，计算与实验吻合，增进了对晶体氨基酸的理解，验证了实验-理论框架。
中文摘要 AI 辅助
氨基酸是生命的基本组成部分，但我们对其固态化学和电子结构的了解仍然有限。固态氨基酸与生物和制药过程相关，因此这一点尤为重要。X射线光电子能谱可有效探测化学状态和占据的电子结构，但大多数氨基酸光谱研究集中在气相物种或表面吸附物，晶体氨基酸研究不足，主要因辐射损伤带来的实验挑战。此外，光谱复杂难解释，促使采用实验-理论结合方法。本研究结合X射线光电子能谱和密度泛函理论计算，系统研究20种蛋白质氨基酸以及可在蛋白质合成中掺入并提供人体所需必需营养素硒的硒代蛋氨酸的核心、半核心和价态。计算出的相对核心结合能与实验结果高度吻合，能可靠地进行归属。态密度投影有助于深入了解局部配位和扩展晶体结构的影响，从而系统地理解固态氨基酸的电子结构和键合。本研究所得见解增进了对晶体氨基酸的理解，并验证了综合实验-理论框架的稳健性。
英文摘要
Amino acids are essential building blocks of life, yet our understanding of their chemistry and electronic structure in the solid state remains limited. This is particularly important because amino acids in the solid state are relevant to biological and pharmaceutical processes. X-ray photoelectron spectroscopy provides a powerful experimental probe of chemical states and occupied electronic structure; however, most spectroscopy studies of amino acids focus on gas-phase species or surface adsorbates, while crystalline amino acids remain underexplored, largely because of experimental challenges associated with radiation damage. Additionally, the spectra are often complex and difficult to interpret, motivating a combined experimental-theoretical approach. This study combines X-ray photoelectron spectroscopy and density functional theory calculations to systematically investigate the core, semi-core, and valence states of 20 proteinogenic amino acids as well as selenomethionine which can be incorporated during protein synthesis and deliver the essential nutrient, Se, required by humans. Calculated relative core binding energies show excellent agreement with experiment and enable reliable assignments. Projections of the density of states provide insight into the influence of local coordination and extended crystal structure, yielding a systematic understanding of the electronic structure and bonding in solid-state AAs. The insights gained from this study enhance the understanding of crystalline amino acids and validate the robustness of an integrated experiment--theory framework.
