1nx6

Crystal Structure of Aspartate Semialdehyde Dehydrogenase from Haemophilus influenzae as a Tetrahedral Hemithiocetal Reaction intermediate with Phosphate at 2.15 A

spinqualitylabelsall models 1nx6, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1nx6 is a 1 chain structure with sequence from Haemophilus influenzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.15Å Ligands: HTI, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DHAS_HAEIN Catalyzes the NADPH-dependent formation of L-aspartate-semialdehyde (L-ASA) by the reductive dephosphorylation of L-aspartyl-4-phosphate. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The structural analysis of an enzymatic reaction intermediate affords a unique opportunity to study a catalytic mechanism in extraordinary detail. Here we present the structure of a tetrahedral intermediate in the catalytic cycle of aspartate-beta-semialdehyde dehydrogenase (ASADH) from Haemophilus influenzae at 2.0-A resolution. ASADH is not found in humans, yet its catalytic activity is required for the biosynthesis of essential amino acids in plants and microorganisms. Diaminopimelic acid, also formed by this enzymatic pathway, is an integral component of bacterial cell walls, thus making ASADH an attractive target for the development of new antibiotics. This enzyme is able to capture the substrates aspartate-beta-semialdehyde and phosphate as an active complex that does not complete the catalytic cycle in the absence of NADP. A distinctive binding pocket in which the hemithioacetal oxygen of the bound substrate is stabilized by interaction with a backbone amide group dictates the R stereochemistry of the tetrahedral intermediate. This pocket, reminiscent of the oxyanion hole found in serine proteases, is completed through hydrogen bonding to the bound phosphate substrate. Capture of an intermediate in the catalytic cycle of L-aspartate-beta-semialdehyde dehydrogenase.,Blanco J, Moore RA, Viola RE Proc Natl Acad Sci U S A. 2003 Oct 28;100(22):12613-7. Epub 2003 Oct 14. PMID:14559965 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aspartate-semialdehyde dehydrogenase 3D structures

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