1gpj: Difference between revisions

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 A 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.

1GPJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanopyrus_kandleri Methanopyrus kandleri] with GMC and CIT as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GPJ OCA].  

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