7q03

Ketol-acid reductoisomerase from Methanothermococcus thermolithotrophicus in the close state with NADP and Mg2+

spinqualitylabelsall models 7q03, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7q03 is a 1 chain structure with sequence from Methanothermococcus thermolithotrophicus DSM 2095. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: EDO, GOL, MG, NAP, SO4, TOE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Ketol-acid reductoisomerase (KARI) orchestrates the biosynthesis of branched-chain amino acids, an elementary reaction in prototrophic organisms as well as a valuable process in biotechnology. Bacterial KARIs belonging to class I organise as dimers or dodecamers and were intensively studied to understand their remarkable specificity towards NADH or NADPH, but also to develop antibiotics. Here, we present the first structural study on a KARI natively isolated from a methanogenic archaea. The dodecameric structure of 0.44-MDa was obtained in two different conformations, an open and close state refined to a resolution of 2.2-A and 2.1-A, respectively. These structures illustrate the conformational movement required for substrate and coenzyme binding. While the close state presents the complete NADP bound in front of a partially occupied Mg(2+)-site, the Mg(2+)-free open state contains a tartrate at the nicotinamide location and a bound NADP with the adenine-nicotinamide protruding out of the active site. Structural comparisons show a very high conservation of the active site environment and detailed analyses point towards few specific residues required for the dodecamerisation. These residues are not conserved in other dodecameric KARIs that stabilise their trimeric interface differently, suggesting that dodecamerisation, the cellular role of which is still unknown, might have occurred several times in the evolution of KARIs. Structural Rearrangements of a Dodecameric Ketol-Acid Reductoisomerase Isolated from a Marine Thermophilic Methanogen.,Lemaire ON, Muller MC, Kahnt J, Wagner T Biomolecules. 2021 Nov 11;11(11). pii: biom11111679. doi: 10.3390/biom11111679. PMID:34827677 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ketol-acid reductoisomerase 3D structures

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