1ADJ

HISTIDYL-TRNA SYNTHETASE IN COMPLEX WITH HISTIDINE

Summary for 1ADJ

• Entry DOI: 10.2210/pdb1adj/pdb
• Descriptor: HISTIDYL-TRNA SYNTHETASE, SULFATE ION, HISTIDINE, ... (4 entities in total)
• Functional Keywords: amino acid, histidine, complex (trna synthetase-peptide), complex (trna synthetase-peptide) complex, complex (trna synthetase/peptide)
• Biological source: Thermus thermophilus
• Total number of polymer chains: 4
• Total formula weight: 189512.57

Authors

Cusack, S.,Aberg, A. (deposition date: 1997-02-18, release date: 1997-08-20, Last modification date: 2024-02-07)

Primary citation

Aberg, A.,Yaremchuk, A.,Tukalo, M.,Rasmussen, B.,Cusack, S.
Crystal structure analysis of the activation of histidine by Thermus thermophilus histidyl-tRNA synthetase.
Biochemistry, 36:3084-3094, 1997

PubMed Abstract: The crystal structure at 2.7 A resolution of histidyl-tRNA synthetase (HisRS) from Thermus thermophilus in complex with its amino acid substrate histidine has been determined. In the crystal asymmetric unit there are two homodimers, each subunit containing 421 amino acid residues. Each monomer of the enzyme consists of three domains: (1) an N-terminal catalytic domain containing a six-stranded antiparallel beta-sheet and the three motifs common to all class II aminoacyl-tRNA synthetases, (2) a 90-residue C-terminal alpha/beta domain which is common to most class IIa synthetases and is probably involved in recognizing the anticodon stem-loop of tRNA(His), and (3) a HisRS-specific alpha-helical domain inserted into the catalytic domain, between motifs II and III. The position of the insertion domain above the catalytic site suggests that it could clamp onto the acceptor stem of the tRNA during aminoacylation. Two HisRS-specific peptides, 259-RGLDYY and 285-GGRYDG, are intimately involved in forming the binding site for the histidine, a molecule of which is found in the active site of each monomer. The structure of HisRS in complex with histidyl adenylate, produced enzymatically in the crystal, has been determined at 3.2 A resolution. This structure shows that the HisRS-specific Arg-259 interacts directly with the alpha-phosphate of the adenylate on the opposite side to the usual conserved motif 2 arginine. Arg-259 thus substitutes for the divalent cation observed in seryl-tRNA synthetase and plays a crucial catalytic role in the mechanism of histidine activation.

PubMed: 9115984
DOI: 10.1021/bi9618373

Experimental method

X-RAY DIFFRACTION (2.7 Å)