Structural highlights
Publication Abstract from PubMedLeucine dehydrogenase (LDH, EC 1.4.1.9) catalyzes the reversible deamination of branched-chain L-amino acids to their corresponding keto acids using NAD(+) as a cofactor. LDH generally adopts an octameric structure with D4 symmetry, generating a molecular mass of approximately 400 kDa. Here, the crystal structure of the LDH from Pseudomonas aeruginosa (Pa-LDH) was determined at 2.5 A resolution. Interestingly, the crystal structure shows that the enzyme exists as a dimer with C2 symmetry in a crystal lattice. The dimeric structure was also observed in solution using multiangle light scattering coupled with size-exclusion chromatography. The enzyme assay revealed that the specific activity was maximal at 60 degrees C and pH 8.5. The kinetic parameters for three different amino acid and the cofactor (NAD(+)) were determined. The crystal structure represents that the subunit has more compact structure than homologs' structure. In addition, the crystal structure along with sequence alignments indicates a set of non-conserved arginine residues which are important in stability. Subsequent mutation analysis for those residues revealed that the enzyme activity reduced to one third of the wild type. These results provide structural and biochemical insights for its future studies on its application for industrial purposes. The Crystal Structure of L-Leucine Dehydrogenase from Pseudomonas aeruginosa.,Kim S, Koh S, Kang W, Yang JK Mol Cells. 2022 Jul 31;45(7):495-501. doi: 10.14348/molcells.2022.0012. Epub 2022, Jun 14. PMID:35698914[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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