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4tqd

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Crystal Structure of the C-terminal domain of IFRS bound with 3-iodo-L-Phe and ATP

Structural highlights

4tqd is a 1 chain structure with sequence from Methanosarcina mazei Go1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.1429Å
Ligands:	, , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

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 PubMed

Pyrrolysyl-tRNA synthetase (PylRS) and its cognate tRNAPyl have emerged as ideal translation components for genetic code innovation. Variants of the enzyme facilitate the incorporation >100 noncanonical amino acids (ncAAs) into proteins. PylRS variants were previously selected to acylate Nepsilon-acetyl-Lys (AcK) onto tRNAPyl. Here, we examine an Nepsilon-acetyl-lysyl-tRNA synthetase (AcKRS), which is polyspecific (i.e., active with a broad range of ncAAs) and 30-fold more efficient with Phe derivatives than it is with AcK. Structural and biochemical data reveal the molecular basis of polyspecificity in AcKRS and in a PylRS variant [iodo-phenylalanyl-tRNA synthetase (IFRS)] that displays both enhanced activity and substrate promiscuity over a chemical library of 313 ncAAs. IFRS, a product of directed evolution, has distinct binding modes for different ncAAs. These data indicate that in vivo selections do not produce optimally specific tRNA synthetases and suggest that translation fidelity will become an increasingly dominant factor in expanding the genetic code far beyond 20 amino acids.

Polyspecific pyrrolysyl-tRNA synthetases from directed evolution.,Guo LT, Wang YS, Nakamura A, Eiler D, Kavran JM, Wong M, Kiessling LL, Steitz TA, O'Donoghue P, Soll D Proc Natl Acad Sci U S A. 2014 Nov 10. pii: 201419737. PMID:25385624^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Guo LT, Wang YS, Nakamura A, Eiler D, Kavran JM, Wong M, Kiessling LL, Steitz TA, O'Donoghue P, Soll D. Polyspecific pyrrolysyl-tRNA synthetases from directed evolution. Proc Natl Acad Sci U S A. 2014 Nov 10. pii: 201419737. PMID:25385624 doi:http://dx.doi.org/10.1073/pnas.1419737111