Team:UST-Beijing/Project

In order to celebrate the power of gene H(orizontal)-transfer between pro- and eukaryotes, we constructed two fusion proteins and tested their function: (1) a synthetic bile acid receptor in E.coli using a mammalian nuclear receptor LXR. As proof-of-principle, the regulatory circuit in symbiotic bacteria could be harmoniously linked to metabolic pathway of their host. Potential application includes in situ synthesis of pharmaceuticals on-demand in the digestive tract. (2) a synthetic light-driven proton pump in human mitocondrial inner membrane using a bacterial proteorhodopsin. Preliminary testing demonstrated cellular sensitivity to light radiation. Application and utility relies on result of in-depth characterization of such system design.

Using lacI DNA-binding domain and LXRbeta ligand-binding domain, we made an artificial bile acid receptor which can regulate expression of target gene within a natural lacI operon. As proof of principle, we demonstrated that regulation of bacteria gene expression by host eukaryocyte metabolites is achievable using chimeric nuclear receptors. Through directed molecular evolution, a harmonious signal network regulating metabolism of both prokaryocytes and their host eukaryocytes in the digestive tract is feasible.

使用大肠杆菌乳糖操纵子和大鼠细胞核受体肝氧化固醇受体配体结合域，我们在大肠杆菌中构建了一个人造胆酸感受器，为消化道内的宿主和寄主的信号协调提供新的途径。

First "reversely" discovered from proteobacteria in 2000，proteorhodopsin (PR) acts as a light-activated proton pump and generates proton motive force across the membrane. We modified PR coding sequence. We replaced its precusor sequence with the leader peptide of human cytochrome cxidase subunit 4 isoform 1, targeting mitochondrial inner membrane. In addition, all the codons were optimized according to codon usage bias for Homo sapiens. As a result, we made a synthetic light-driven proton pump and positioned it on the inner membrane of mitochondria, which under certain conditions, can positvely use light energy to drive human cells in vitro.

通过改造变形紫色红质的编码区和信号肽，我们在体外培养的人细胞内植入一种新的人造蛋白。该蛋白可接受光能，并转化成化学势能，最终转化为化学能。