Team:Paris/Perspectives

Biosynthetic Bottum-up approach

The field of artificial molecular machines and motors is growing at an astonishing rate and is attracting a great deal of interest in nanoscience. Research in the last decade has shown that species made of components like DNA or proteins are more attractive candidate. Our aims is to build by a bottom-up approched DNA nanocars that have the properties to produce energy in vitro. Our system is more efficient than a classic system because the FIFO order is very important: the first part will assembled with part 2 and then with part 3. If part 3 will attached to part 1, part 2 will not attached and the DNA car will be incomplete.

Fig.1:biosynthesis by sequential expression of 3 DNA origami

If we add in vitro a complementary miRNA to the red regions, the competition will delivered minimun ten time more energy than ATP biodegradation (winfree et.al), the instability of the miRNA may make this processe reversible. In conclusion, these kinds of DNA structures can be suitable, reversible and metastable DNA fuels and a new kind of cargo delivery machine.

We can also produce a lot of differentes kinds of self-assembly structures like virus:

Fig2: Biosynthesis by sequential expresssion of gag,env and P10

Metabolic engineering of polyhydroxyalkanoate biosynthesis pathways

Human overpopulation combined with the current lifestyle urges the rational, efficient, and sustainable use of natural resources to produce environmentally friendly plastic materials such as polyhydroxyalkanoic acids (PHAs), whose production/degradation cycle reduces undesirable wastes and emissions. Our study is a new metabolic strategy to generate PHA-hyperproducer strains, that have the properties to be a sequential metabolic pathway, we believe the sequential expression may increases the production of purified PHA.

Our strategy consists on replacing the RFP,CFP and YFP genes by the PhaA ,PhaB and PhaC genes in our final system (containing oscillation,FIFO,synchronisation modules).

This strategy is more efficient than a constitutive activation for 3 main reasons:

• First, in this application the NADPH, which is a cellular metastable fuel, is used by the PhaB to synthesize bioplastic. This molecule is very important for many metabolic pathways in bacteria. A NADPH recuperation step is then needed to ensure other metabolic activities to go on. We can then make the hypothesis that if the PhaB is always activated the bacteria will get exhausted and die quickly (4-5 days). In our system, the bacteria will have a NADPH recuperation step, this is why we hope bacteria will live more than in an usual chemoreactor.

• Secondly, we hope by the order of the FIFO to make a synchronized and sequential turn-over of the enzymatic expression in order to increase the rate of the PHA biosynthesis.

• Third, as the quality of the bioplastic increases with time, we could predict the quality of the final product since we would know the duration of a production cycle thanks to the periodicity of our system.

Bibliography