Three-dimensional architecture of the eukaryotic multisynthetase complex determined from negatively stained and cryoelectron micrographs.

This study provides the first description of the three-dimensional architecture of the multienzyme complex of aminoacyl-tRNA synthetases. Reconstructions were calculated from electron microscopic images of negatively stained and frozen hydrated samples using three independent angular assignment methods. In all cases, volumes show an asymmetric triangular arrangement of protein domains around a deep central cavity. The structures have openings or indentations on most sides. Maximum dimensions are ca. 19x16x10 nm. The central cavity is 4 nm in diameter and extends two-thirds of the length of the particle.