法国艾克斯-马赛大学F. Beisson等研究人员合作揭示脂肪酸光脱羧酶的机理和动力学。相关论文于2021年4月9日发表在《科学》杂志上。

通过结合静态的、时间分辨的低温捕获光谱学、晶体学和计算分析，研究人员表征了小球藻（Chlorella variabilis）脂肪酸光脱羧酶（FAP）反应中间体的时间范围（从亚皮秒到毫秒）。来自同步加速器和自由电子激光X射线源的高分辨率晶体结构突出了氧化黄素发色团的不寻常弯曲形状。

研究人员证明，脱羧作用直接发生在脂肪酸底物还原激发的黄素上。随着黄素通过烷基自由基中间体的再氧化，大部分裂解的二氧化碳意外地在100纳秒内转化，最有可能转化为碳酸氢盐。该反应比溶液中的反应快几个数量级。两个严格保守的残基R451和C432对于底物稳定和功能性电荷转移至关重要。

据悉，FAP是一种具有潜在绿色化学应用的光酶。

附：英文原文

Title: Mechanism and dynamics of fatty acid photodecarboxylase

Author: D. Sorigué, K. Hadjidemetriou, S. Blangy, G. Gotthard, A. Bonvalet, N. Coquelle, P. Samire, A. Aleksandrov, L. Antonucci, A. Benachir, S. Boutet, M. Byrdin, M. Cammarata, S. Carbajo, S. Cuiné, R. B. Doak, L. Foucar, A. Gorel, M. Grünbein, E. Hartmann, R. Hienerwadel, M. Hilpert, M. Kloos, T. J. Lane, B. Légeret, P. Legrand, Y. Li-Beisson, S. L. Y. Moulin, D. Nurizzo, G. Peltier, G. Schirò, R. L. Shoeman, M. Sliwa, X. Solinas, B. Zhuang, T. R. M. Barends, J.-P. Colletier, M. Joffre, A. Royant, C. Berthomieu, M. Weik, T. Domratcheva

Issue&Volume: 2021/04/09

Abstract: Fatty acid photodecarboxylase (FAP) is a photoenzyme with potential green chemistry applications. By combining static, time-resolved, and cryotrapping spectroscopy and crystallography as well as computation, we characterized Chlorella variabilis FAP reaction intermediates on time scales from subpicoseconds to milliseconds. High-resolution crystal structures from synchrotron and free electron laser x-ray sources highlighted an unusual bent shape of the oxidized flavin chromophore. We demonstrate that decarboxylation occurs directly upon reduction of the excited flavin by the fatty acid substrate. Along with flavin reoxidation by the alkyl radical intermediate, a major fraction of the cleaved carbon dioxide unexpectedly transformed in 100 nanoseconds, most likely into bicarbonate. This reaction is orders of magnitude faster than in solution. Two strictly conserved residues, R451 and C432, are essential for substrate stabilization and functional charge transfer.

DOI: 10.1126/science.abd5687

Source: https://science.sciencemag.org/content/372/6538/eabd5687