V-shaped structure of glutamyl-tRNA reductase, the first enzyme of tRNA-dependent tetrapyrrole biosynthesis
AUTOR(ES)
Moser, Jürgen
FONTE
Oxford University Press
RESUMO
Processes vital to life such as respiration and photosynthesis critically depend on the availability of tetrapyrroles including hemes and chlorophylls. tRNA-dependent catalysis generally is associated with protein biosynthesis. An exception is the reduction of glutamyl-tRNA to glutamate-1-semialdehyde by the enzyme glutamyl-tRNA reductase. This reaction is the indispensable initiating step of tetrapyrrole biosynthesis in plants and most prokaryotes. The crystal structure of glutamyl-tRNA reductase from the archaeon Methanopyrus kandleri in complex with the substrate-like inhibitor glutamycin at 1.9 Å resolution reveals an extended yet planar V-shaped dimer. The well defined interactions of the inhibitor with the active site support a thioester-mediated reduction process. Modeling the glutamyl-tRNA onto each monomer reveals an extensive protein–tRNA interface. We furthermore propose a model whereby the large void of glutamyl-tRNA reductase is occupied by glutamate-1-semialdehyde-1,2-mutase, the subsequent enzyme of this pathway, allowing for the efficient synthesis of 5-aminolevulinic acid, the common precursor of all tetrapyrroles.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125327Documentos Relacionados
- Expression of a Soybean Gene Encoding the Tetrapyrrole-Synthesis Enzyme Glutamyl-tRNA Reductase in Symbiotic Root Nodules1
- Biosynthesis of Tetrapyrrole Pigment Precursors 1: Formation and Utilization of Glutamyl-tRNA for δ-Aminolevulinic Acid Synthesis by Isolated Enzyme Fractions from Chlorella Vulgaris
- The structure of an AspRS–tRNAAsp complex reveals a tRNA-dependent control mechanism
- tRNA synthetase paralogs: Evolutionary links in the transition from tRNA-dependent amino acid biosynthesis to de novo biosynthesis
- Cloning of the Glutamyl-tRNA Synthetase (gltX) Gene from Pseudomonas aeruginosa
