Kuhar Nikki, Sil Sanchita, Umapathy Siva
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560 012, Karnataka, India.
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560 012, Karnataka, India; Defence Bioengineering and Electromedical Laboratory (DEBEL), Defence Research and Development Organization (DRDO), C V Raman Nagar, Bangalore 560 093, Karnataka, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Sep 5;258:119712. doi: 10.1016/j.saa.2021.119712. Epub 2021 Apr 20.
Proteins are large, complex molecules responsible for various biological processes. However, protein misfolding may lead to various life-threatening diseases. Therefore, it is vital to understand the shape and structure of proteins. Despite numerous techniques, a mechanistic understanding of the protein folding process is still unclear. Therefore, new techniques are continually being explored. In the present article, we have discussed the importance of Raman spectroscopy, Raman Optical Activity (ROA) and various other advancements in Raman spectroscopy to understand protein structure and conformational changes based on the review of our earlier work and recent literature. A Raman spectrum of a protein provides unique signatures for various secondary structures like helices, beta-sheets, turns, random structures, etc., and various amino acid residues such as tyrosine, tryptophan, and phenylalanine. We have shown how Raman spectra can differentiate between bovine serum albumin (BSA) and lysozyme protein based on their difference in sequence and structure (primary, secondary and tertiary). Although it is challenging to elucidate the structure of a protein using a Raman spectrum alone, Raman spectra can be used to differentiate small changes in conformations of proteins such as BSA during melting. Various new advancements in technique and data analyses in Raman spectroscopic studies of proteins have been discussed. The last part of the review focuses on the importance of the ROA spectrum to understand additional features about proteins. The ROA spectrum is rich in information about the protein backbone due to its rigidity compared to its side chains. Furthermore, the ROA spectra of lysozyme and BSA have been presented to show how ROA provides extra information about the solvent properties of proteins.
蛋白质是负责各种生物过程的大型复杂分子。然而，蛋白质错误折叠可能导致各种危及生命的疾病。因此，了解蛋白质的形状和结构至关重要。尽管有众多技术，但对蛋白质折叠过程的机理理解仍不清楚。因此，新技术不断被探索。在本文中，基于我们早期的工作和近期文献的综述，我们讨论了拉曼光谱、拉曼光学活性（ROA）以及拉曼光谱的各种其他进展在理解蛋白质结构和构象变化方面的重要性。蛋白质的拉曼光谱为各种二级结构（如螺旋、β-折叠、转角、无规结构等）以及各种氨基酸残基（如酪氨酸、色氨酸和苯丙氨酸）提供独特的特征。我们展示了拉曼光谱如何根据牛血清白蛋白（BSA）和溶菌酶蛋白质在序列和结构（一级、二级和三级）上的差异来区分它们。尽管仅使用拉曼光谱阐明蛋白质的结构具有挑战性，但拉曼光谱可用于区分蛋白质（如BSA）在熔化过程中构象的微小变化。本文讨论了蛋白质拉曼光谱研究中技术和数据分析的各种新进展。综述的最后一部分重点介绍了ROA光谱在理解蛋白质其他特征方面的重要性。由于ROA光谱中蛋白质主链相对于其侧链具有刚性，因此它富含有关蛋白质主链的信息。此外，还展示了溶菌酶和BSA的ROA光谱，以说明ROA如何提供有关蛋白质溶剂性质的额外信息。
