RUI: Determination of the orientation of 13C labeled specific residues of alpha-synuclein(61-95) in the pore structure formed on supported phospholipids bilayer by IRRAS

在这个由化学系化学结构、动力学和机制B项目资助的项目中，田纳西中部州立大学化学系的王成山教授正在研究一种蛋白质--α-突触核蛋白的聚集体结构，这种蛋白质在人脑中含量丰富，与帕金森氏症有关。α-突触核蛋白形成两种类型的聚集体：成熟纤维和低聚物。众所周知，成熟的纤维是无毒的，但寡聚体可以通过在细胞膜上形成孔结构来导致神经细胞的死亡。了解低聚物聚集体的结构将为帕金森病治疗药物的开发提供线索。参与该项目的本科生和研究生包括第一代和代表性不足的少数族裔学生，他们正在学习可能影响他们职业选择的研究领域。此外，正在为研究生级别的有机化学课程开发一项新的多肽合成实验室实验。已经开发了各种技术来确定蛋白质的结构。其中，傅里叶变换红外光谱(FTIR)具有快速响应的特点，已被用于蛋白质和多肽的各种构象(如α-螺旋、β-折叠、非结构构象)的研究。这种方法利用了酰胺I带，它是由于主链酰胺键中的羰基的伸缩方式而产生的。传统的FTIR只能提供整体构象的一小部分信息。为了扩大它的能力，可以在主链酰胺键上的羰基上引入13C标记，并生成一个新的带(13C酰胺I带)来确定特定残基的构象。在本项目中，将13C标记引入到α-突触核蛋白的序列中，以研究α-突触核蛋白低聚体在残基水平上的构象。此外，还利用红外反射吸收光谱研究了~(13)C标记的羰基化合物的取向。结合构象和取向信息，可以在磷脂双层结构中评价α-突触核蛋白的结构。

In this project funded by the Chemical Structure, Dynamics & Mechanism B Program of the Chemistry Division, Professor Chengshan Wang of the Chemistry Department at Middle Tennessee State University is studying the structure of aggregates of a protein, alpha-synuclein, that is abundant in the human brain and that has been linked to Parkinson's disease. Alpha-synuclein forms two types of aggregates: mature fibrils and oligomers. The mature fibrils are known to be non-toxic, but oligomers can cause the death of the neuronal cells by forming pore structure in the cell membrane. Understanding the structure of oligomer aggregates should provide clues for the development of therapeutic agents for Parkinson's disease. Undergraduate and graduate students working on this project include first-generation and underrepresented minority students who are learning about research areas that could influence their career choices. In addition, a new laboratory experiment on peptide synthesis for a graduate level organic chemistry class is being developed. Various techniques have been developed to determine the structure of proteins. Among them, Fourier transform infrared spectroscopy (FTIR) provides a fast response and has been used to evaluate various conformations (such as alpha-helix, beta-sheet, unstructured conformation) in proteins and peptides. This method utilizes the amide I band, which arises from the stretching mode of the carbonyl group in the backbone amide bonds. Traditional FTIR can only provide information about an overall fraction of the conformations. To expand its capability, 13C labels can be introduced to the carbonyls in the backbone amide bonds and a new band (the 13C amide I band) can be generated to determine the conformation of specific residues. In this project, 13C labels are introduced into the sequence of alpha-synuclein to study the conformation of the oligomers of alpha-synuclein at the residue level. In addition, Infrared Reflection-Absorption Spectroscopy is used to address the orientation of 13C labeled carbonyls. With both conformation and orientation information, the structure of alpha-synuclein can be evaluated in phospholipid bilayer structures.