| Primary Identifier | IPR042078 | Type | Homologous_superfamily |
| Short Name | Lys-tRNA-ligase_SC_fold |
| description | Lysine-tRNA ligase (also knowns as lysyl-tRNA synthetase) () is an alpha 2 homodimer that belong to both class I and class II. In eubacteria and eukaryota lysine-tRNA ligases belong to class II in the same family as aspartate tRNA ligase. The class Ic lysine-tRNA ligase family is present in archaea and in a number of bacterial groups that include the alphaproteobacteria and spirochaetes[]. A refined crystal structures shows that the active site of lysU is shaped to position the substrates for the nucleophilic attack of the lysine carboxylate on the ATP alpha-phosphate. No residues are directly involved in catalysis, but a number of highly conserved amino acids and three metal ions coordinate the substrates and stabilise the pentavalent transition state. A loop close to the catalytic pocket, disordered in the lysine-bound structure, becomes ordered upon adenine binding [].The structure of LysRS-I is composed of 5 domains: a Rossmann-fold domain (domain 1), a helical insertion (Ins 1), a CP domain (domain 2), a SC-fold domain (domain 3) an α-helix bundle-like domain (domain 4) and an α-helix cage domain (domain 5).This entry represents the stem contact fold (SC-fold) domain found in Lysine tRNA ligase. |
