Crystal Structure of Asparagine Synthetase Reveals a Close Evolutionary Relationship to Class II Aminoacyl-tRNA Synthetase (MOLECULAR BIOFUNCTION-Functional Molecular Conversion)

Abstract

The crystal structure of E. coli asparagine synthetase has been determined by X-ray diffraction analysis at 2.5 A resolution. The overall structure of the enzyme is remarkably similar to that of the catalytic domain of yeast aspartyl-tRNA synthetase despite low sequence similarity. These enzymes have a common reaction mechanism that implies the formation of aminoacyl-adenylate intermediate. The active site architecture and most of the catalytic residues are also conserved in both enzymes. These enzymes have probably evolved from a common ancestor even though their sequence similarities are small.