Crystal structure studies of NADP+ dependent isocitrate dehydrogenase from Thermus thermophilus exhibiting a novel terminal domain

Kumar, Shankar; Pampa, K.J.; Manjula, M.; Abdoh, Muneer; Kunishima, N.; Lokanath, N.K.

doi:10.1016/j.bbrc.2014.04.164

Cited by 4 publications

(1 citation statement)

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“…These IDHs were structurally distinguished from other dimeric IDHs, as they were longer in the C-terminal region. Although they were assigned as subfamily IV IDHs in two recent studies 28 29 , they were included as type I IDHs in our study, as they shared considerable sequence identities (>40%) with mitochondrial NAD-IDHs.…”

Section: Resultsmentioning

confidence: 99%

Novel Type II and Monomeric NAD+ Specific Isocitrate Dehydrogenases: Phylogenetic Affinity, Enzymatic Characterization and Evolutionary Implication

Wang

Zhu

2015

Sci Rep

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NAD+ use is an ancestral trait of isocitrate dehydrogenase (IDH), and the NADP+ phenotype arose through evolution as an ancient adaptation event. However, no NAD+-specific IDHs have been found among type II IDHs and monomeric IDHs. In this study, novel type II homodimeric NAD-IDHs from Ostreococcus lucimarinus CCE9901 IDH (OlIDH) and Micromonas sp. RCC299 (MiIDH), and novel monomeric NAD-IDHs from Campylobacter sp. FOBRC14 IDH (CaIDH) and Campylobacter curvus (CcIDH) were reported for the first time. The homodimeric OlIDH and monomeric CaIDH were determined by size exclusion chromatography and MALDI-TOF/TOF mass spectrometry. All the four IDHs were demonstrated to be NAD+-specific, since OlIDH, MiIDH, CaIDH and CcIDH displayed 99-fold, 224-fold, 61-fold and 37-fold preferences for NAD+ over NADP+, respectively. The putative coenzyme discriminating amino acids (Asp326/Met327 in OlIDH, Leu584/Asp595 in CaIDH) were evaluated, and the coenzyme specificities of the two mutants, OlIDH R326H327 and CaIDH H584R595, were completely reversed from NAD+ to NADP+. The detailed biochemical properties, including optimal reaction pH and temperature, thermostability, and metal ion effects, of OlIDH and CaIDH were further investigated. The evolutionary connections among OlIDH, CaIDH, and all the other forms of IDHs were described and discussed thoroughly.

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Section: Resultsmentioning

confidence: 99%