Photoactivatable enzyme upconverting lanthanide nanoparticle conjugates for low energy light driven biocatalysis

作为推动更可持续的技术和绿色化学合成的一部分，生物催化转化在当今经济中正变得越来越重要。1利用太阳能实现光生物催化更具吸引力，最近在这一领域进行了几项有影响力的创新。重要的是，光活化化学可以产生新的化学途径和在热催化中未知的新化合物，开辟新的化学空间。在这方面，紫外光或可见(蓝)光的光生物催化已经发展起来，利用光氧化还原催化剂和光和/或激活的酶利用非自然的电子转移过程来获得新的酶功能。在这里，我们提出了一种新的替代传统的高能紫外光-蓝光激活的酶催化方法，通过利用更多的太阳光谱，并利用酶-UCNP偶联物中的稀土元素上转换纳米颗粒(UCNPs)2(将近红外光(NIR)转换为紫外光或可见光)来实现光激活的生物催化。在化学、生物、分析化学和物理的界面上，该项目将涉及制造一系列旧的黄酶家族的黄素酶和NADP(H)依赖的酶，这些酶被共价拴在能够促进低能光生物催化的UCNPs上。将对催化性能进行评估，并确定热催化和光催化(紫外可见和近红外)激活的催化在产物方面的差异。激发态和瞬时自由基物种的性质将提供重要的机械信息，这些信息将由一套EPR技术与位于曼彻斯特的EPSRC国家EPR服务合作进行询问。此外，还将使用正交化学方法将不同的酶连接到同一纳米颗粒上，以探索多组分和级联的光生物催化的可能性，例如3以及原位生物连接策略的发展。

Biocatalytic transformations are gaining increasing importance in todays' economy as part of the drive towards more sustainable technology and green chemical synthesis.1 Harnessing solar energy to achieve photo-biocatalysis is even more attractive and several impactful innovations have recently been made in this field. Importantly, light activated chemistry can lead to new chemical pathways and new compounds hitherto unknown in thermal catalysis, opening up new chemical space. In this regard, photo-biocatalysis with UV or visible (blue) light has been developed with photoredox catalyts and light and/or activated enzymes using non-natural electron transfer processes to access new enzyme function. Here, we propose a new alternative to traditional high energy UV-blue light activated enzyme photocatalysis by exploiting more of the solar spectrum and taking advantage of lanthanide upconverting nanoparticles (UCNPs)2 in enzyme-UCNP conjugates (which convert near infra-red light (nIR) to UV or visible light) to enable light activated biocatalysis. At the interface of chemistry, biology, analytical chemistry and physics, this project will involve fabrication of a range of flavoenzymes of the old yellow enzyme family and NADP(H) dependent enzymes that are covalently tethered to UCNPs capable of promoting low energy photo-biocatalysis. Catalytic performance will be assessed and the difference between thermal and photo (UV-visible vs. nIR) activated catalysis in terms of the products produced established. The nature of the excited states and transient radical species will give important mechanistic information and these will be interrogated by a suite of EPR techniques in collaboration with the EPSRC National EPR service in Manchester. Additionally, the possibility of multicomponent and cascade photo-biocatalysis will be investigated using orthogonal chemistries to conjugate different enzymes to the same nanoparticle for example3 as well as the development of in situ bioconjugation strategies.