Acta Crystallographica Section F

Structural Biology and Crystallization Communications

Volume 61, Part 1 (January 2005)

crystallization communications

Acta Cryst. (2005). F61, 30-32 [ doi:10.1107/S1744309104021827 ]

Crystallization of leucyl-tRNA synthetase complexed with tRNA^Leu from the archaeon Pyrococcus horikoshii

R. Fukunaga, R. Ishitani, O. Nureki and S. Yokoyama

Abstract: All five tRNA^Leu isoacceptors from the archaeon Pyrococcus horikoshii have been transcribed in vitro and purified. The leucyl-tRNA synthetase (LeuRS) from P. horikoshii was overexpressed in Escherichia coli and purified, and cocrystallizations with each of the tRNA^Leu isoacceptors were attempted. Cocrystals were obtained by the hanging-drop vapour-diffusion method, but only when the tRNA^Leu isoacceptor with the anticodon CAA was used. Electrophoretic analyses revealed that the crystals contain both LeuRS and tRNA^Leu, suggesting that they are LeuRS-tRNA^Leu complex crystals. A data set diffracting to 3.3 Å resolution was collected from a single crystal at 100 K. The crystal belongs to the orthorhombic space group P2₁2₁2, with unit-cell parameters a = 118.18, b = 120.55, c = 231.13 Å. The asymmetric unit is expected to contain two complexes of LeuRS-tRNA^Leu, with a corresponding crystal volume per protein weight of 2.9 Å³ Da^-1 and a solvent content of 57.3%.

Keywords: LeuRS; tRNA; leucine; identity; Pyrococcus horikoshii; long variable loop.