Phosphoribosylglycinamide synthetase catalyses the second step in the de novo biosynthesis of purine. The reaction catalysed by Phosphoribosylglycinamide synthetase is the ATP- dependent addition of 5-phosphoribosylamine to glycine to form 5'phospho ...
Phosphoribosylglycinamide synthetase catalyses the second step in the de novo biosynthesis of purine. The reaction catalysed by Phosphoribosylglycinamide synthetase is the ATP- dependent addition of 5-phosphoribosylamine to glycine to form 5'phosphoribosylglycinamide. This domain is related to the ATP-grasp domain of biotin carboxylase/carbamoyl phosphate synthetase (see Pfam:PF02786).
Glutathione biosynthesis is achieved in most organisms via a conserved two-step approach relying on the capacity of two independent and unrelated ligases to perform peptide synthesis coupled to ATP hydrolysis. In a first and rate-limiting step, gamma ...
Glutathione biosynthesis is achieved in most organisms via a conserved two-step approach relying on the capacity of two independent and unrelated ligases to perform peptide synthesis coupled to ATP hydrolysis. In a first and rate-limiting step, gamma-glutamylcysteine ligase (gamma-ECL) (or GshA; EC:6.3.2.2) uses l-glutamate and l-cysteine to form gamma-glutamylcysteine (gamma-EC), which, in a second step, is condensed with glycine to glutathione by glutathione synthetase (GS) (or GshB; EC:6.3.2.3). However, several pathogenic and free-living bacteria carry out glutathione biosynthesis based on a single enzyme that catalyzes both the gamma-ECL and the GS reactions. Such bifunctional glutathione-synthesizing enzymes have been termed gamma-GCS-GS or GshF [1]. Hybrid GshF contains a typical gamma-proteobacterial gamma-ECL fused to an ATP-grasp-like domain [2]. The ATP-grasp-like module is responsible for the ensuing formation of glutathione from gamma-glutamylcysteine and glycine. The ATP-grasp-like domain has an antiparallel beta-sheet in the GshF structures in contrast to all structurally characterized members of the ATP-grasp superfamily [1].