1htt

The crystal structure at 2.6 A of the histidyl-tRNA synthetase from Escherichia coli complexed with histidyl-adenylate has been determined. The enzyme is a homodimer with a molecular weight of 94 kDa and belongs to the class II of aminoacyl-tRNA synthetases (aaRS). The asymmetric unit is composed of two homodimers. Each monomer consists of two domains. The N-terminal catalytic core domain contains a six-stranded antiparallel beta-sheet sitting on two alpha-helices, which can be superposed with the catalytic domains of yeast AspRS, and GlyRS and SerRS from Thermus thermophilus with a root-mean-square difference on the C alpha atoms of 1.7-1.9 A. The active sites of all four monomers are occupied by histidyl-adenylate, which apparently forms during crystallization. The 100 residue C-terminal alpha/beta domain resembles half of a beta-barrel, and provides an independent domain oriented to contact the anticodon stem and part of the anticodon loop of tRNA(His). The modular domain organization of histidyl-tRNA synthetase reiterates a repeated theme in aaRS, and its structure should provide insight into the ability of certain aaRS to aminoacylate minihelices and other non-tRNA molecules.

Crystal structure of histidyl-tRNA synthetase from Escherichia coli complexed with histidyl-adenylate., Arnez JG, Harris DC, Mitschler A, Rees B, Francklyn CS, Moras D, EMBO J. 1995 Sep 1;14(17):4143-55. PMID:7556055

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

Proteopedia Page Contributors and Editors (what is this?)

OCA

Categories: Escherichia coli | Histidine--tRNA ligase | Single protein | Arnez, J G. | Francklyn, C S. | Harris, D C. | Mitschler, A. | Moras, D. | Rees, B. | Aminoacyl-trna synthase | Ligase | Synthetase