3eia

Crystal structure of K270Q variant of LL-diaminopimelate aminotransferase from Arabidopsis thaliana complexed with L-Glu: External aldimine form

spinqualitylabelsall models 3eia, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3eia is a 2 chain structure with sequence from Arath. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PL6, SO4 Related: 3ei5, 3ei6, 3ei7, 3ei8, 3ei9, 3eib Gene: DAP, AGD2, At4g33680, T16L1.170 (ARATH) Activity: LL-diaminopimelate aminotransferase, with EC number 2.6.1.83 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DAPAT_ARATH] Required for lysine biosynthesis. Catalyzes the direct conversion of tetrahydrodipicolinate to LL-diaminopimelate, a reaction that requires three enzymes in E.coli. Not active with meso-diaminopimelate, lysine or ornithine as substrates. 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 LL-Diaminopimelate aminotransferase (LL-DAP-AT), a pyridoxal phosphate (PLP)-dependent enzyme in the lysine biosynthetic pathways of plants and Chlamydia, is a potential target for the development of herbicides or antibiotics. This homodimeric enzyme converts L-tetrahydrodipicolinic acid (THDP) directly to LL-DAP using L-glutamate as the source of the amino group. Earlier, we described the 3D structures of native and malate-bound LL-DAP-AT from Arabidopsis thaliana (AtDAP-AT). Seven additional crystal structures of AtDAP-AT and its variants are reported here as part of an investigation into the mechanism of substrate recognition and catalysis. Two structures are of AtDAP-AT with reduced external aldimine analogues: N-(5'-phosphopyridoxyl)-L-glutamate (PLP-Glu) and N-(5'-phosphopyridoxyl)- LL-Diaminopimelate (PLP-DAP) bound in the active site. Surprisingly, they reveal that both L-glutamate and LL-DAP are recognized in a very similar fashion by the same sets of amino acid residues; both molecules adopt twisted V-shaped conformations. With both substrates, the alpha-carboxylates are bound in a salt bridge with Arg404, whereas the distal carboxylates are recognized via hydrogen bonds to the well-conserved side chains of Tyr37, Tyr125 and Lys129. The distal C(epsilon) amino group of LL-DAP is specifically recognized by several non-covalent interactions with residues from the other subunit (Asn309*, Tyr94*, Gly95*, and Glu97* (Amino acid designators followed by an asterisk (*) indicate that the residues originate in the other subunit of the dimer)) and by three bound water molecules. Two catalytically inactive variants of AtDAP-AT were created via site-directed mutagenesis of the active site lysine (K270N and K270Q). The structures of these variants permitted the observation of the unreduced external aldimines of PLP with L-glutamate and with LL-DAP in the active site, and revealed differences in the torsion angle about the PLP-substrate bond. Lastly, an apo-AtDAP-AT structure missing PLP revealed details of conformational changes induced by PLP binding and substrate entry into the active site. Mechanism of substrate recognition and PLP-induced conformational changes in LL-diaminopimelate aminotransferase from Arabidopsis thaliana.,Watanabe N, Clay MD, van Belkum MJ, Cherney MM, Vederas JC, James MN J Mol Biol. 2008 Dec 31;384(5):1314-29. Epub 2008 Oct 15. PMID:18952095 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

Proteopedia Page Contributors and Editors (what is this?)

OCA