5N5U image
Deposition Date 2017-02-14
Release Date 2018-02-14
Last Version Date 2024-01-17
Entry Detail
PDB ID:
5N5U
Keywords:
Title:
Structure of p-boronophenylalanyl tRNA synthetase in complex with p-boronophenylalanine and adenosine monophosphate
Biological Source:
Method Details:
Experimental Method:
Resolution:
1.60 Å
R-Value Free:
0.21
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
P 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Tyrosine--tRNA ligase
Gene (Uniprot):tyrS
Mutations:M6L, Y32S, L65A, H70M, D158S, L162E
Chain IDs:A
Chain Length:314
Number of Molecules:1
Biological Source:Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440)
Primary Citation
Structural Basis for the Specific Cotranslational Incorporation of p-Boronophenylalanine into Biosynthetic Proteins.
Biochemistry 57 2597 2600 (2018)
PMID: 29668275 DOI: 10.1021/acs.biochem.8b00171

Abstact

The site-specific incorporation of the non-natural amino acid p-boronophenylalanine (Bpa) into recombinant proteins enables the development of novel carbohydrate-binding functions as well as bioorthogonal chemical modification. To this end, Bpa is genetically encoded by an amber stop codon and cotranslationally inserted into the recombinant polypeptide chain at the ribosome by means of an artificial aminoacyl-tRNA synthetase (aaRS) in combination with a compatible suppressor tRNA. We describe the crystal structure of an aaRS specific for Bpa, which had been engineered on the basis of the TyrRS from Methanocaldococcus jannaschii, in complex with both Bpa and AMP. The substrates are bound in an orientation resembling the aminoacyl-AMP mixed anhydride intermediate and engaged in a network of four hydrogen bonds that allows specific recognition of the boronate moiety by the aaRS. The key determinant of this interaction is the coplanar alignment of its Glu162 carboxylate group with Bpa, which results in a double hydrogen bond with the boronic acid substituent. Our structural study elucidates how a small set of five side chain exchanges within the TyrRS active site can switch its substrate specificity to the hydrophilic amino acid Bpa, thus stimulating the reprogramming of other aaRS to recruit useful non-natural amino acids for next-generation protein engineering.

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Primary Citation of related structures