Bioretrosynthesis

Bioretrosynthesis is a technique for synthesizing organic chemicals from inexpensive precursors and evolved enzymes.^[1] The technique builds on the retro-evolution hypothesis proposed in 1945 by geneticist Norman Horowitz.^[2]

Technique

The technique works backwards from the target to identify a precursor molecule and an enzyme that converts it into the target, and then a second precursor that can produce the first and so on until a simple, inexpensive molecule becomes the beginning of the series.^[1]

For each precursor, the enzyme is evolved using induced mutations and natural selection to produce a more productive version. The evolutionary process can be repeated over multiple generations until acceptable productivity is achieved.^[1]

The process does not require high temperature, high pressure, the use of exotic catalysts or other elements that can increase costs.^[1]

The enzyme "optimizations" that increase the production of one precursor from another are cumulative in that the same precursor productivity improvements can potentially be leveraged across multiple target molecules.^[1]

Didanosine

In 2014 the technique was used to produce the HIV drug didanosine.^[2]

A simpler molecule was identified that can be converted into didanosine when subjected to a specific chemical transformation in the presence of a specific enzyme.^[2]

The gene that creates the enzyme was then "copied", adding random mutations to each copy using ribokinase engineering.^[2]

The mutant genes were inserted into Escherichia coli bacteria and used to produce (now-mutant) enzymes. The enzymes were then mixed with the precursor and the mutant enzymes that produced the greatest amount of didanosine were retained and replicated. One mutant stimulated a 50x increase in didanosine production.^[2]

The first step was repeated, using the first precursor in place of didanosine, finding a yet simpler precursor and an enzyme to produce it. One mutated enzyme produced a 9,500x increase in nucleoside production.^[2]

A third retrogression allowed them to start with the simple and inexpensive sugar named dideoxyribose and produce didanosine in a three-step sequence.^[2]

References

1 2 3 4 5 "The bioretrosynthesis solution: shifting evolution into reverse to make cheaper drugs". KurzweilAI. 2014-04-09. doi:10.1038/nchembio.1494. Retrieved 2014-04-09.
Birmingham, W. R.; Starbird, C. A.; Panosian, T. D.; Nannemann, D. P.; Iverson, T. M.; Bachmann, B. O. (2014). "Bioretrosynthetic construction of a didanosine biosynthetic pathway". Nature Chemical Biology. doi:10.1038/nchembio.1494.
1 2 3 4 5 6 7 "Shifting evolution into reverse promises cheaper, greener way to make new drugs". ScienceDaily. doi:10.1038/nchembio.1494. Retrieved 2014-04-09.

External links

"Bio-RetroSynthesis Team — Institute of Systems & Synthetic Biology". Issb.genopole.fr. Retrieved 2014-04-09.

Chemical synthesis

Types	Artificial gene synthesis Biomimetic synthesis Bioretrosynthesis Biosynthesis Convergent synthesis Custom peptide synthesis Direct process Divergent synthesis Electrosynthesis Enantioselective synthesis Fully automated synthesis Hydrothermal synthesis LASiS Mechanosynthesis One-pot synthesis Organic synthesis Peptide synthesis Radiosynthesis Semisynthesis Solid-phase synthesis Solvothermal synthesis Total synthesis Volume combustion synthesis

Chemical synthesis Category:Chemical synthesis

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