A unique homodimeric NAD ⁺ ‐linked isocitrate dehydrogenase from the smallest autotrophic eukaryote Ostreococcus tauri

Abstract

29, 2462-2472 (2015). www.fasebj.org

Biochemical Characterization and Complete Conversion of Coenzyme Specificity of Isocitrate Dehydrogenase from Bifidobacterium longum

“…Furthermore, Arg314 in Hc IDH forms a salt bridge with Asp253′ (equivalent to Asp253′ in Bl IDH) and interacts with Arg249′ and Gln257′ [ 15 ]. As compared with NAD-IDH, Arg314 and His315 in Bl IDH are replaced by Asp357 and Ile358 in Acidithiobacillus thiooxidans NAD-IDH ( At IDH) from Type I subfamily [ 26 ] and Asp344 and Met345 in Ostreococcus tauri NAD-IDH ( Ot IDH) from Type II subfamily [ 13 ]. Asp253′, Ser257′ and Lys260′ in Bl IDH are substituted with Ala279′, Lys283′ and Gln286′ in Ot IDH, as shown in Figure 3 .…”

“…Several NAD-dependent IDHs have converted their coenzyme specificities from NAD + to NADP + by strategic amino acid replacements, such as NAD-IDHs from Micromonas sp. [ 12 ], O. tauri [ 13 ] and C. litoralis [ 30 ].…”

“…The homodimeric NADP-IDHs from eukaryotes (in cytoplasm and mitochondria) and some bacterial NADP-IDHs are categorized into the Type II subfamily. It was noted that, recently, several algae IDHs were found to be Type II NAD-IDHs, whose coenzyme specificity can be completely converted from NAD + to NADP + by rational mutagenesis [ 12 , 13 ]. All monomeric enzymes, either NAD + or NADP + -dependent, fall into the third subfamily.…”

Crystal Structure of the Isocitrate Dehydrogenase 2 from Acinetobacter baumannii (AbIDH2) Reveals a Novel Dimeric Structure with Two Monomeric-IDH-Like Subunits

“…When taking into consideration the coenzyme specificity, the IDH protein family can be very divergent. Our previous works have redefined the phylogenesis of the IDH protein family [ 7 , 8 , 9 ]. Three diverse phylogenetic subfamilies can be distinguished among all IDHs.…”

“…Type I IDHs are composed of homo-dimeric NAD(P)-IDHs from archaea and bacteria, as well as homo-tetrameric NAD(P)-IDHs from bacteria and hetero-oligomeric NAD-IDHs from mitochondria. Type II IDHs are mainly comprised of homo-dimeric NADP-IDHs from bacteria and eukaryotes, with a newly found group of homo-dimeric NAD-IDHs from marine bacteria and algae [ 7 , 9 ]. Although IDHs from type I and II subfamilies share similar protein size and topology, their primary sequence identities are less than 15%.…”