7Q07

Ketol-acid reductoisomerase from Methanothermococcus thermolithotrophicus in the open state with NADP and tartrate

Summary for 7Q07

• Entry DOI: 10.2210/pdb7q07/pdb
• Descriptor: Ketol-Acid Reductoisomerase from Methanothermococcus thermolithotrophicus, L(+)-TARTARIC ACID, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: ketol-acid reductoisomerase, kari, methanogenic archaea, conformational rearrangement, native purification, oligomerization, thermophile, branched-chain amino acid, biosynthesis, isomerase
• Biological source: Methanothermococcus thermolithotrophicus DSM 2095
• Total number of polymer chains: 1
• Total formula weight: 37618.66

Authors

Lemaire, O.N.,Mueller, M.,Wagner, T. (deposition date: 2021-10-14, release date: 2021-12-08, Last modification date: 2024-01-31)

Primary citation

Lemaire, O.N.,Muller, M.C.,Kahnt, J.,Wagner, T.
Structural Rearrangements of a Dodecameric Ketol-Acid Reductoisomerase Isolated from a Marine Thermophilic Methanogen.
Biomolecules, 11:-, 2021

PubMed Abstract: 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-Å and 2.1-Å, 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-site, the Mg-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.

PubMed: 34827677
DOI: 10.3390/biom11111679

Experimental method

X-RAY DIFFRACTION (2.2 Å)