Team:Paris/Perspectives

More general applications

As for the flagella biosynthesis our FIFO could be useful for many bottom-up assembled molecular machines that needs to be assembled in a precise order. For instance ,the type III secretion injectisome. The Injectisome is a complex nanomachine that allows bacteria to deliver protein effector across eucaryotic cellular membranes. The injectisom consists of a basal structure, which resembles the basal structure of the flagellum,surmounted by either a needle ,a needle and a filament or a long pilus[ref].

The injectisome is related to the flagellum genetically studies show that a core of eight proteins share significant similarity with components of the flagellum from this study we can expected that the genes expression is rule by a sequential FIFO order like the flagellum biosynthesis .

Example of an application: 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. One illustrative example is polyhydroxyalkanoic acids (PHAs), whose production/degradation cycle reduces undesirable wastes and emissions. The biosynthesis of this polymer is currently subject to intensive work. It consists in expressing in appropriate quantities 3 enzymes PhaA ,PhaB and PhaC that sequentialy process AcetoacetylcoA into its final product PHA. This biosynthesis os subjected to 2 contraints :

• Intermediate products of this pathway are used in alternatives competing metabolic pathways,
• Only the final product is of interest,so that all intermediates products need to be transformed into PHA.

two strategies are commonly used in bioengineering of methabolics pathways :

• Sequential expression of enzymes involved in the pathways,
• Or constitutive expressions of all enzymes.

Because of the above mentioned limitations, none of these approches are adapted here . Using the sequential expression, intermediate products would accumulate and thus be consummed by competing pathways. Using the constitutive expression a mixture of final and intermediate product would necessarily be obtained.

Our FIFO could be useful here. Indeed a FIFO expression pattern is intermediate between a purely sequential and a purely constitutive expression. At some point all enzymes are presents ( no accumulation of intermediate products ) and during the last step only the last enzyme (PhC) is presents ( all intermediate products are consummed). Moreover, the fact that our system oscillate could provide to the cell a metabolic recovering phase.