Lee, BI Chang, C Cho, SJ Eom, SH Kim, KK Yu, YG Suh, SW 2024-01-21T12:33:21Z 2024-01-21T12:33:21Z 2021-09-01 2001-04-13 0022-2836 https://pubs.kist.re.kr/handle/201004/140532 MJ0490 gene, one of the only two genes of Methanococcus jannaschii showing sequence similarity to the lactate/malate family of dehydrogenases, was classified initially as coding for a putative L-lactate dehydrogenase (LDH). It has been re-classified as a malate dehydrogenase (MDH) gene, because it shows significant sequence similarity to MT0188, MDH II from Methanobacterium thermoautotrophicum strain DeltaH. The three-dimensional structure of its gene product has been determined in two crystal forms: a "dimeric" structure in the orthorhombic crystal at 1.9 Angstrom resolution and a "tetrameric" structure in the tetragonal crystal at 2.8 Angstrom. These structures share a similar subunit fold with other LDHs and MDHs. The tetrameric structure resembles typical tetrameric LDHs. The dimeric structure is equivalent to the P-dimer of tetrameric LDHs, unlike dimeric MDHs, which correspond to the Q-dimer. The structure reveals that the cofactor NADP(H) is bound at the active site, despite the fact that it was not intentionally added during protein purification and crystallization. The preference of NADP(H) over NAD(H) has been supported by activity assays. The cofactor preference is explained by the presence of a glycine residue in the cofactor binding pocket (Gly33), which replaces a conserved aspartate (or glutamate) residue in other NAD-dependent LDHs or MDHs. Preference for NADP(H) is contributed by hydrogen bonds between the oxygen atoms of the monophosphate group and the ribose sugar of adenosine in NADP(H) and the side-chains of Ser9, Arg34, His36, and Ser37. The MDH activity of MJ0490 is made possible by Arg86, which is conserved in MDHs but not in LDHs. The enzymatic assay showed that the MJ0490 protein possesses the fructose-1,6-bisphosphate-activated LDH activity (reduction). Thus the MJ0490 gene product appears to be a novel member of the lactate/malate dehydrogenase family, displaying an LDH scaffold and exhibiting a relaxed substrate and cofactor specificities in NADP(H) and NAD(H)-dependent malate and lactate dehydrogenase reactions. (C) 2001 Academic Press. English ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD CYTOPLASMIC MALATE-DEHYDROGENASE TERNARY COMPLEX BACILLUS-STEAROTHERMOPHILUS THERMOTOGA-MARITIMA SEQUENCE ASSOCIATION SPECIFICITY REFINEMENT REDESIGN REVEALS Crystal structure of the MJ0490 gene product of the hyperthermophilic archaebacterium Methanococcus jannaschii, a novel member of the lactate/malate family of dehydrogenases Article 10.1006/jmbi.2001.4532 1 JOURNAL OF MOLECULAR BIOLOGY, v.307, no.5, pp.1351 - 1362 JOURNAL OF MOLECULAR BIOLOGY 307 5 1351 1362 scie scopus 000168386000016 2-s2.0-0035853289 Biochemistry & Molecular Biology Biochemistry & Molecular Biology Article CYTOPLASMIC MALATE-DEHYDROGENASE TERNARY COMPLEX BACILLUS-STEAROTHERMOPHILUS THERMOTOGA-MARITIMA SEQUENCE ASSOCIATION SPECIFICITY REFINEMENT REDESIGN REVEALS crystal structure lactate dehydrogenase malate dehydrogenase Methanococcus jannaschii NADPH