Peking University, Dec. 7 2010: Recently, latest advance in chemical biology was published in the Journal of the American Chemical Society in research on fluorescent probes by Chen Peng Research Group of College of Chemistry and Molecular Engineering, Peking University.

Cheng Peng Research Group of the Department of Chemical Biology discovered that the transcriptional regulatory protein OhrR is converted into a fluorescent bioprobe capable of detecting organic hydroperoxides (OHPs) in living cells with high sensitivity and selectivity, presenting the design, construction, and characterization of organic hydroperoxide sensor (OHSer), a novel protein-based fluorescent indicator for optical imaging of intracellular OHPs. The unique oxidative response mechanism of the template protein Xc-OhrR enables OHSer to effectively discriminate OHPs against competing cellular reactive oxidative species (ROS).
In the research paper, they illustrated the design and characterization of a novel genetically encoded fluorescent probe for selective visualization of OHPs in living systems. The design strategy is inspired by the unique feature of OhrR, a transcriptional regulator in control of the OHP detoxification apparatus that is widely conserved in bacteria.

They finally constructed an organic peroxide fluorescent probe which was highly selective by combining OhrR and the ring of cpVenus. This peroxide fluorescent probe, which can effectively respond to fluorescent organic peroxide free radical, do not react with hydrogen peroxide, superoxide anion, singlet oxygen, hydroxyl radicals and other substances.

With the aid of this technique, they realized for the first time in the world real-time and dynamic fluorescence observation on the organic peroxide free radical in living cells with high selectivity. Organic peroxide free radical is usually considered far more damaging to human cells than hydrogen peroxide. However, the lack of specific recognition probes has hindered us from understanding the behaviors and mechanism of the free radicals in the physiological and pathological conditions. The new fluorescent probe will make great contributions to the research in the pathogenic mechanism of organic peroxide free radicals in the living cells. 
The results have been published in the November 15, 2010 online issue of JACS (Journal of the American Chemical Society), titled “A Highly Selective Fluorescent Probe for Visualization of Organic Hydroperoxides in Living Cells”.

Reactive Oxygen Species（ROS）stand for a series of the oxygen atoms and free radical compounds with highly active chemical properties. These compounds, directly related to cancer, aging diseases, body inflammation, DNA damage and cell signaling has been the focus of researches in the field of basic medical and life sciences. Due to the short life span of reactive oxygen species in vivo and the very subtle differences between various types of reactive oxygen species, it is one of the most difficult and forefront problem that how to identify a specific type of reactive oxygen species in real time and highly selectively for vivo imaging.

Translated by: Ma Xiao
Edited by: Zhang Chunlan
Source: PKU News (Chinese)