BGI Research Reveals the Mutual Orthogonal Molecular Mechanism of Novel PylRS/tRNAPyl

The use of gene codon expansion technology to introduce unnatural amino acids into proteins can endow the target protein with new physical and chemical properties.

On April 25, 2022, a team from Shenzhen BGI Life Sciences Research Institute published online at Nucleic Acids Research (IF=17) entitled "The tRNA discriminator base defines the mutual orthogonality of two distinct pyrrolysyl-tRNA synthetase/tRNA ^Pyl pairs in the same organism”, which unearthed two novel PylRS/tRNA ^Pyl pairs that coexist in the halophilic methanogenic archaea Candidatus Methanohalarchaeum thermophilum HMET1 , using the model halophilic archaea H, which is closely related to HMET1.

The study first established a bioinformatic method for mining PylRS/tRNA ^{Pyl pairings, identified all PylRS enzymes that only contain catalytic domains in archaea, and found two coexisting PylRS/tRNA Pyl} pairs in the halophilic methanogen HMET1.

Since the HMET1-derived PylRS enzyme is insoluble in E.

What is the molecular basis for the maintenance of mutual orthogonality between the 2 target PylRS/tRNA ^{Pyl pairs?} According to the structural prediction of the interaction with tRNA ^Pyl in PylRS enzymes , the authors found that the conserved motif 2 loops (used to recognize discriminative bases in tRNA ^Pyl ) in the two target PylRS enzymes have different lengths (Figure 3).

In order to further prove the orthogonality of the two pairs of target PylRS/tRNA ^Pyl pairing and the value of subsequent applications, the authors constructed a PylRS1-SI enzyme that can specifically recognize the unnatural amino acid 3-I-Phe based on the PylRS1 enzyme, and constructed a PylRS1-SI enzyme.

Associate Researcher Fu Xian and Researcher Shen Yue from Shenzhen BGI Life Sciences Research Institute, and Professor Dieter Söll from Yale University are the co-corresponding authors of the paper