Université Lille1 Sciences et Technologies, 59655 Villeneuve d'Ascq, France.
Anal Bioanal Chem. 2011 Feb;399(6):1999-2014. doi: 10.1007/s00216-010-4325-0.
Two-dimensional correlation analysis was carried out in combination with multivariate curve resolution-alternating least squares (MCR-ALS) to analyse time-resolved infrared (IR) difference spectra probing photoinduced ubiquinol formation in detergent-isolated reaction centres from Rhodobacter sphaeroides. The dynamic 2D IR correlation spectra have not only allowed the determination of the concomitance or non-concomitance of different chemical events through known marker bands but also have helped identify new vibrational bands related to the complex series of photochemical and redox reactions. In particular, a strong positive band located at 1565 cm⁻¹ was found to be synchronous with the process of ubiquinol formation. In addition, a tailored MCR-ALS analysis was performed using a priori chemical knowledge of the system, in particular including the pure spectrum of one species obtained from an external measurement. Enhancing the MCR-ALS performance in this way in time-dependent processes is relevant, especially when other essential pieces of information, such as kinetic models, are unavailable. The results give evidence of four independent spectral contributions. Three of them show marker bands for a monoelectronic reduction of the primary quinone QA (QA⁻/QA transition, first contribution), for a monoelectronic reduction of a secondary quinone QB (QB⁻/QB transition, second contribution) and for ubiquinol formation (third contribution). The results obtained also confirm that a key rate-limiting factor is the slow ubiquinone and ubiquinol exchange among micelles, which strongly influences the kinetic profiles of the involved species.
采用二维相关分析结合多元曲线分辨-交替最小二乘法（MCR-ALS）分析了从球形红杆菌去污剂分离的反应中心中光诱导泛醌形成的时间分辨红外（IR）差谱。动态二维 IR 相关光谱不仅允许通过已知的标记带确定不同化学事件的伴随或非伴随性，还有助于鉴定与复杂的光化学和氧化还原反应系列相关的新振动带。特别是，发现位于 1565cm⁻¹处的强正带与泛醌形成过程同步。此外，还使用系统的先验化学知识（特别是包括从外部测量获得的一种物质的纯光谱）进行了定制的 MCR-ALS 分析。在这种情况下，在时间相关过程中增强 MCR-ALS 的性能是相关的，特别是当没有其他重要信息（如动力学模型）时。结果证明存在四个独立的光谱贡献。其中三个显示了一个电子还原的初级醌 QA 的标记带（QA⁻/QA 跃迁，第一个贡献），一个电子还原的二级醌 QB 的标记带（QB⁻/QB 跃迁，第二个贡献）和泛醌形成（第三个贡献）。结果还证实，一个关键的限速因素是胶束间泛醌和泛醇的缓慢交换，这强烈影响了所涉及物质的动力学谱。
