4m52 | pdb_00004m52

Structure of Mtb Lpd bound to SL827

spinqualitylabelsall models 4m52, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4m52 is a 4 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FAD, M52 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DLDH_MYCTU Lipoamide dehydrogenase is an essential component of the alpha-ketoacid dehydrogenase complexes, namely the pyruvate dehydrogenase (PDH) complex, the branched-chain alpha-ketoacid dehydrogenase (BCKADH) complex, and likely also the 2-oxoglutarate dehydrogenase (ODH) complex. Catalyzes the reoxidation of dihydrolipoyl groups which are covalently attached to the lipoate acyltransferase components (E2) of the complexes. Is also able to catalyze the transhydrogenation of NADH and thio-NAD(+) in the absence of D,L-lipoamide, and the NADH-dependent reduction of quinones in vitro. Together with AhpC, AhpD and DlaT, Lpd constitutes an NADH-dependent peroxidase active against hydrogen and alkyl peroxides as well as serving as a peroxynitrite reductase, thus protecting the bacterium against reactive nitrogen intermediates and oxidative stress generated by the host immune system. Appears to be essential for Mtb pathogenesis. Publication Abstract from PubMed Tuberculosis remains a global health emergency that calls for treatment regimens directed at new targets. Here we explored lipoamide dehydrogenase (Lpd), a metabolic and detoxifying enzyme in Mycobacterium tuberculosis (Mtb) whose deletion drastically impairs Mtb's ability to establish infection in the mouse. Upon screening more than 1.6 million compounds, we identified N-methylpyridine 3-sulfonamides as potent and species-selective inhibitors of Mtb Lpd affording >1000-fold selectivity versus the human homologue. The sulfonamides demonstrated low nanomolar affinity and bound at the lipoamide channel in an Lpd-inhibitor cocrystal. Their selectivity could be attributed, at least partially, to hydrogen bonding of the sulfonamide amide oxygen with the species variant Arg93 in the lipoamide channel. Although potent and selective, the sulfonamides did not enter mycobacteria, as determined by their inability to accumulate in Mtb to effective levels or to produce changes in intracellular metabolites. This work demonstrates that high potency and selectivity can be achieved at the lipoamide-binding site of Mtb Lpd, a site different from the NAD+/NADH pocket targeted by previously reported species-selective triazaspirodimethoxybenzoyl inhibitors. Lipoamide Channel-Binding Sulfonamides Selectively Inhibit Mycobacterial Lipoamide Dehydrogenase.,Bryk R, Arango N, Maksymiuk C, Balakrishnan A, Wu YT, Wong CH, Masquelin T, Hipskind P, Lima CD, Nathan C Biochemistry. 2013 Nov 26. PMID:24251446 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dihydrolipoamide dehydrogenase

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