2abw
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(New page: 200px<br /><applet load="2abw" size="350" color="white" frame="true" align="right" spinBox="true" caption="2abw, resolution 1.620Å" /> '''Glutaminase subunit...)
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Revision as of 15:58, 29 January 2008
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Glutaminase subunit of the plasmodial PLP synthase (Vitamin B6 biosynthesis)
Overview
Vitamin B6 is one of nature's most versatile cofactors. Most organisms, synthesize vitamin B6 via a recently discovered pathway employing the, proteins Pdx1 and Pdx2. Here we present an in-depth characterization of, the respective orthologs from the malaria parasite, Plasmodium falciparum., Expression profiling of Pdx1 and -2 shows that blood-stage parasites, indeed possess a functional vitamin B6 de novo biosynthesis. Recombinant, Pdx1 and Pdx2 form a complex that functions as a glutamine, amidotransferase with Pdx2 as the glutaminase and Pdx1 as pyridoxal-5, '-phosphate synthase domain. Complex formation is required for catalytic, activity of either domain. Pdx1 forms a chimeric bi-enzyme with the, bacterial YaaE, a Pdx2 ortholog, both in vivo and in vitro, although this, chimera does not attain full catalytic activity, emphasizing that, species-specific structural features govern the interaction between the, protein partners of the PLP synthase complexes in different organisms. To, gain insight into the activation mechanism of the parasite bi-enzyme, complex, the three-dimensional structure of Pdx2 was determined at 1.62 A., The obstruction of the oxyanion hole indicates that Pdx2 is in a resting, state and that activation occurs upon Pdx1-Pdx2 complex formation.
About this Structure
2ABW is a Single protein structure of sequence from Plasmodium falciparum with as ligand. Full crystallographic information is available from OCA.
Reference
Vitamin B6 biosynthesis by the malaria parasite Plasmodium falciparum: biochemical and structural insights., Gengenbacher M, Fitzpatrick TB, Raschle T, Flicker K, Sinning I, Muller S, Macheroux P, Tews I, Kappes B, J Biol Chem. 2006 Feb 10;281(6):3633-41. Epub 2005 Dec 8. PMID:16339145
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