Subjects: Biology >> Biophysics submitted time 2016-05-18
Liu, Xiaohong
Jiang, Li
Li, Jiasong
Wang, Li
Zhou, Qing
Lv, Xiaoxuan
Gong, Weimin
Wang, Jiangyun
Lu, Yi
Lu, Yi
Yu, Yang
Abstract： Photo-induced electron transfer (PET) is ubiquitous for photosynthesis and fluorescent sensor design. However, genetically coded PET sensors are underdeveloped, due to the lack of methods to site-specifically install PET probes on proteins. Here we describe a family of acid and Mn(III) turn-on fluorescent protein (FP) sensors, named iLovU, based on PET and the genetic incorporation of superior PET quenchers in the fluorescent flavoprotein iLov. Using the iLovU PET sensors, we monitored the cytoplasmic acidification process, and achieved Mn(III) fluorescence sensing for the first time. The iLovU sensors should be applicable for studying pH changes in living cells, monitoring biogentic Mn(III) in the environment, and screening for efficient manganese peroxidase, which is highly desirable for lignin degradation and biomass conversion. Our work establishes a platform for many more protein PET sensors, facilitates the de novo design of metalloenzymes harboring redox active residues, and expands our ability to probe protein conformational dynamics.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Biophysics >> Biochemistry & Molecular Biology submitted time 2016-05-12
Abstract： The oxygen-evolving center (OEC) in photosystem II catalyzes a water splitting reaction. Great efforts have already been made to artificially synthesize the OEC, in order to elucidate the structure-function relationship and the mechanism of the reaction. Now, a new synthetic model makes the best mimic yet of the OEC. This recent study opens up the possibility to study the mechanism of photosystem II and photosynthesis in general for applications in renewable energy and synthetic biology.
Peer Review Status:Awaiting Review
Subjects: Biology >> Biophysics submitted time 2016-05-12
Abstract： Terminal oxidases catalyze four-electron reduction of oxygen to water, and the energy harvested is utilized to drive the synthesis of adenosine triphosphate. While much effort has been made to design a catalyst mimicking the function of terminal oxidases, most biomimetic catalysts have much lower activity than native oxidases. Herein we report a designed oxidase in myoglobin with an O-2 reduction rate (52 s(-1)) comparable to that of a native cytochrome (cyt) cbb(3) oxidase (SO s(-1)) under identical conditions. We achieved this goal by engineering more favorable electrostatic interactions between a functional oxidase model designed in sperm whale myoglobin and its native redox partner, cyt b(5), resulting in a 400-fold electron transfer (ET) rate enhancement. Achieving high activity equivalent to that of native enzymes in a designed metalloenzyme offers deeper insight into the roles of tunable processes such as ET in oxidase activity and enzymatic function and may extend into applications such as more efficient oxygen reduction reaction catalysts for biofuel cells.
Peer Review Status:Awaiting Review
Subjects: Biology >> Biophysics submitted time 2016-05-11
Lv, Xiaoxuan
Hu, Cheng
Gao, Feng
Li, Jiasong
Liu, Xiaohong
Deng, Kai
Zheng, Peng
Gong, Weimin
Wang, Jiangyun
Lv, Xiaoxuan
Hu, Cheng
Gao, Feng
Li, Jiasong
Liu, Xiaohong
Deng, Kai
Zheng, Peng
Gong, Weimin
Wang, Jiangyun
Zhou, Meng
Xia, Andong
Abstract： Electron transfer (ET) is widely used for driving the processes that underlie the chemistry of life. However, our abilities to probe electron transfer mechanisms in proteins and design redox enzymes are limited, due to :the lack of methods to site-specifically insert electron acceptors into proteins in vivo. Here we describe the synthesis and genetic incorporation of 4-fluoro-3-nitrophenylalanine (FNO(2)Phe), which has similar reduction potentials to NAD(P)H and ferredoxin, the most important biological reductants. Through the genetic incorporation of FNO2Phe into green fluorescent:protein (GFP) and femtosecond transient absorption measurement, we show that photoinduced electron transfer (PET) from the GFP chromophore to FNO2Phe occurs very fast (within 11 ps), which is comparable to that of the first electron transfer step in photosystem I, from P700* to A(0). This genetically encoded, low-reduction potential unnatural amino acid (UAA) can significantly in-Trove our ability to investigate electron transfer mechanisms in complex reductases and facilitate the design of miniature proteins that mimic their functions.
Peer Review Status:Awaiting Review
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