Related Experiment Video
Updated: Apr 20, 2026

Site Specific Lysine Acetylation of Histones for Nucleosome Reconstitution using Genetic Code Expansion in Escherichia coli
Published on: December 26, 2020
Crystal structures of Entamoeba histolytica lysyl-tRNA synthetase reveal conformational changes upon lysine binding
Luc Bonnefond1, Manuel Castro de Moura, Lluis Ribas de Pouplana
1Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 113-0032, Japan. lbonnefond@unistra.fr
Abstract:
The class II lysyl-tRNA synthetases (KRS) are conserved aminoacyl-tRNA synthetases that attach lysine to the cognate tRNA in a two-step mechanism. The enzyme from the parasitic protozoan Entamoeba histolytica was crystallized in the presence of small ligands to generate snapshots of the lysine-adenylate formation. The residues involved in lysine activation are highly conserved and the active site closes around the lysyl-adenylate, as observed in bacterial KRS. The Entamoeba EMAPII-like polypeptide is not resolved in the crystals, but another Entamoeba-specific insertion could be modeled as a small helix bundle that may contribute to tRNA binding through interaction with the tRNA hinge.
Related Concept Videos
tRNA Activation
Ligand Binding and Linkage
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
Cooperative Allosteric Transitions
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...

