How Many Biochemistries Are Available To Build a Cell?

Area of Science:

• Synthetic biology
• Microbial genetics
• Biochemistry

Background:

• The genetic code is fundamental to all life, dictating protein synthesis.
• Modifying the genetic code offers pathways to novel biological functions and biomaterials.
• Escherichia coli is a model organism for genetic manipulation and experimental evolution.

Purpose of the Study:

• To engineer a noncanonical genetic code in Escherichia coli.
• To replace the endogenous amino acid tryptophan with a synthetic analog.
• To demonstrate the feasibility of complete amino acid replacement through experimental evolution.

Main Methods:

• Manual experimental evolution of Escherichia coli over 506 days.
• Selection for organisms capable of utilizing a thienylpyrrole-based building block.
• Genetic and biochemical analyses to confirm the replacement of tryptophan.

Main Results:

• Achieved complete replacement of endogenous tryptophan with a synthetic thienylpyrrole-based building block.
• Successfully designed and implemented a noncanonical genetic code in Escherichia coli.
• Demonstrated the stability and viability of the engineered strain.

Conclusions:

• Experimental evolution is a viable strategy for redesigning the genetic code.
• Complete replacement of an endogenous amino acid with a synthetic one is achievable.
• This work opens possibilities for novel protein engineering and synthetic biology applications.