Abstract:Life is anti-entropic and highly organized phenomenon with two characteristics reinforcing each other: homochirality and the stereospecific catalysis of chemical reactions. The exclusive presence of L-amino acids and R-sugars in living world well depict this. Hypothetically, the amino acids and sugars of reverse chirality could form a parallel kingdom which is highly orthogonal to the present world. The components from this mirror kingdom, such as protein or nucleic acid, will be much more resistant to the defensive mechanism of present living system, which could be of great value. Therefore, we are asking if we could, by gradually rewiring the present bio-machineries, build a bridge leading us to the space of mirror-imaged biomolecules. We begin by investigating protein synthesis with mirror amino acid since most of it contains one chiral center to be inversed comparing to sugars. In this work, we analyzed three stages critical for the incorporation of D-amino acid into ribosomal protein synthesis: amino acylation, EF-Tu binding of amino acyl-tRNA and delivery bias, and ribosome catalyzed peptidyl transfer. We have demonstrated that the affinity between EF-Tu and amino acyl-tRNA plays critical role on D-amino acid incorporation, and built a platform aim to select for ribosome tolerating D-amino acid better.