Structural highlights
Function[PYLS_METMA] Catalyzes the attachment of pyrrolysine to tRNA(Pyl). Pyrrolysine is a lysine derivative encoded by the termination codon UAG (By similarity). Publication Abstract from PubMedPyrrolysyl-tRNA synthetase (PylRS) is a major tool in genetic code expansion using noncanonical amino acids, yet its structure and function are not completely understood. Here we describe the crystal structure of the previously uncharacterized essential N-terminal domain of this unique enzyme in complex with tRNAPyl. This structure explains why PylRS remains orthogonal in a broad range of organisms, from bacteria to humans. The structure also illustrates why tRNAPyl recognition by PylRS is anticodon independent: the anticodon does not contact the enzyme. Then, using standard microbiological culture equipment, we established a new method for laboratory evolution-a noncontinuous counterpart of the previously developed phage-assisted continuous evolution. With this method, we evolved novel PylRS variants with enhanced activity and amino acid specificity. Finally, we employed an evolved PylRS variant to determine its N-terminal domain structure and show how its mutations improve PylRS activity in the genetic encoding of a noncanonical amino acid. Crystal structures reveal an elusive functional domain of pyrrolysyl-tRNA synthetase.,Suzuki T, Miller C, Guo LT, Ho JML, Bryson DI, Wang YS, Liu DR, Soll D Nat Chem Biol. 2017 Oct 16. doi: 10.1038/nchembio.2497. PMID:29035363[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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