Characterization of two mutually orthogonal pyrrolysyl-tRNA synthetase/tRNAPyl pairs residing in the same organism

ABSTRACT: Site-specific incorporation of distinct non-canonical amino acids (ncAAs) into proteins via genetic code expansion requires mutually orthogonal aminoacyl-tRNA synthetase (aaRS)/tRNA pairs. Pyrrolysyl–tRNA synthetase (PylRS)/tRNAPyl pairs are ideal for genetic code expansion and have been extensively engineered for developing mutually orthogonal pairs. Here, we identify two novel PylRS/tRNAPyl pairs from extremely halophilic methyl-reducing euryarchaeal HMET1. In order to demonstrate that HMET1 PylRS/tRNAPyl pairs are functional and orthogonal in H. volcanii, we transformed plasmids encoding HMET1 PylRS/tRNAPyl pair and reporter protein SAMP1(G24amb), and cultured the cells in the presence and absence of 1 mM ncAA. Amber suppression ability of HMET1 PylRS/tRNAPyl pairs were assayed by monitoring the production of the full-length SAMP1(G24amb) and the SAMP1(G24amb)-MoaE conjugate via anti-Flag immunoblotting. LC-MS/MS confirmed that BocK (ncAA) was incorporated into the reporter protein at site-directed position. Thus, these two distinct PylRS/tRNAPyl pairs are functional in Haloferax volcanii, a model halophilic archaeon. Furthermore, by swapping these two PylRS/tRNAPyl pairs in the expression vector followed by anti-Flag immunoblotting, we found these two PylRS/tRNAPyl pairs are mutually orthogonal. Finally, we demonstrate HMET1 PylRS/tRNAPyl-derived pairs can decode two stop codons and incorporate distinct ncAAs. LC-MS/MS analysis of the purified reporter protein confirmed that BocK and 3-I-phe were incorporated at the TAA and TAG-directed positions respectively.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Haloferax Volcanii (halobacterium Volcanii)

SUBMITTER: Yuxing Zhang  

LAB HEAD: Xian Fu

PROVIDER: PXD027053 | Pride | 2022-05-12

REPOSITORIES: Pride