2cin

Lysine aminotransferase from M. tuberculosis in the internal aldimine form

spinqualitylabelsall models 2cin, resolution 1.98Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2cin is a 1 chain structure with sequence from Mycobacterium tuberculosis H37Rv. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.98Å Ligands: PLP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function LAT_MYCTU 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 Lysine epsilon-aminotransferase (LAT) is a PLP-dependent enzyme that is highly up-regulated in nutrient-starved tuberculosis models. It catalyzes an overall reaction involving the transfer of the epsilon-amino group of L-lysine to alpha-ketoglutarate to yield L-glutamate and alpha-aminoadipate-delta-semialdehyde. We have cloned and characterized the enzyme from Mycobacterium tuberculosisH37Rv. We report here the crystal structures of the enzyme, the first from any source, in the unliganded form, external aldimine with L-lysine, with bound PMP and with its C5 substrate alpha-ketoglutarate. In addition to interaction details in the active site, the structures reveal a Glu243 "switch" through which the enzyme changes substrate specificities. The unique substrate L-lysine is recognized specifically when Glu243 maintains a salt-bridge with Arg422. On the other hand, the binding of the common C5 substrates L-glutamate and alpha-ketoglutarate is enabled when Glu243 switches away and unshields Arg422. The structures reported here, sequence conservation and earlier mutational studies suggest that the "glutamate switch" is an elegant solution devised by a subgroup of fold type I aminotransferases for recognition of structurally diverse substrates in the same binding site and provides for reaction specificity. Direct evidence for a glutamate switch necessary for substrate recognition: crystal structures of lysine epsilon-aminotransferase (Rv3290c) from Mycobacterium tuberculosis H37Rv.,Mani Tripathi S, Ramachandran R J Mol Biol. 2006 Oct 6;362(5):877-86. Epub 2006 Aug 11. PMID:16950391 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Aminotransferase 3D structures

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