Green DPSS laser for nanoparticles characterization by SERS and rRaman spectroscopy of heme proteins

我们需要一个工作在532 nm的窄线宽二极管泵浦固态（DPSS）激光器，用于获得血红素蛋白的共振拉曼（rRaman）光谱（如当前M. Couture发现资助所述）和纳米材料的表面增强拉曼光谱（SERS），以构建将用作血管系统模型的流动细胞（如B. Mutus发现资助所述）。M. Couture拥有强大的科学计划，旨在详细表征一氧化氮合酶（nos）的催化机制，一氧化氮合酶是合成信号分子一氧化氮的酶。为此，她的实验室配备了高分辨率拉曼系统，用于获得nos和其他血红素蛋白的拉曼光谱。目前的装置使用激光在吸收光谱的蓝色区域发射，以获得稳定样品的拉曼光谱，以及使用定制的连续流混合器获得短寿命动力学中间体的拉曼光谱。所要求的绿色DPSS激光将允许血红素活性位点的q波段（绿色）激发，以特异性地增强血红素的非完全对称模式。这将补充我们目前的蓝色激发研究，对确定血红素大环和血红素取代基的模式非常重要。一旦指定，特定的血红素模式可以揭示NOSs的半胱氨酸硫上的电子密度如何与血红素共享，它如何响应底物和辅因子的结合，以及这与NOSs的催化过程如何相关。

We request a narrow linewidth Diode-Pumped Solid State (DPSS) laser operating at 532 nm that will be used to obtain resonance Raman (rRaman) spectra of heme proteins (as described in current M. Couture Discovery Grant) and Surface-Enhanced Raman Spectra (SERS) of nanomaterial synthesized in order to build a flow-cell that will be used as a model of the vascular system (as described in B. Mutus Discovery Grant). M. Couture has a strong scientific program aimed at the detailed characterization of the catalytic mechanism of nitric oxide synthases (NOSs), which are the enzymes that synthesize the signalling molecule nitric oxide. For this, her laboratory is equiped with a high resolution Raman system that is used to get rRaman spectra of NOSs and other heme proteins. The current set-up uses a laser emitting in the blue-region of the absorption spectrum to get rRaman spectra of stable samples as well as those of short-lived kinetic intermediates using a custom-build continuous flow mixer. The requested green DPSS laser would allow Q-band (green) excitation of the heme active site to specifically enhance non-totally symmetric modes of the heme. This would complement our current studies with blue-excitation and be extremely important to assign the modes of the heme macrocycle and of the heme substituents. Once assigned, specific heme modes could reveal how the electron density on the cysteine sulfur of NOSs is shared with the heme, how it responds to substrate and cofactor binding and how this relates to the catalytic process in NOSs.