Three-dimensional reconstruction of the valyl-tRNA synthetase/elongation factor-1H complex and localization of the delta subunit.

Eukaryotic valyl-tRNA synthetase (ValRS) and the heavy form of elongation factor 1 (EF-1H) are isolated as a stable high molecular mass complex that catalyzes consecutive steps in protein biosynthesis--aminoacylation of tRNA and its transfer to elongation factor. Herein is the first three-dimensional structure of the particle as calculated from electron microscopic images of negatively stained samples of the human ValRS/EF-1H complex. The ca.

A three-dimensional working model of the multienzyme complex of aminoacyl-tRNA synthetases based on electron microscopic placements of tRNA and proteins.

It has become evident that the process of protein synthesis is performed by many cellular polypeptides acting in concert within the structural confines of protein complexes. In multicellular eukaryotes, one of these assemblies is a multienzyme complex composed of eight proteins that have aminoacyl-tRNA synthetase activities as well as three non-synthetase proteins (p43, p38, and p18) with diverse functions. This study uses electron microscopy and three-dimensional reconstruction to explore the arrangement of proteins and tRNA substrates within this "core" multisynthetase complex.