4y1p
Crystal structure of 3-isopropylmalate dehydrogenase (Saci_0600) from Sulfolobus acidocaldarius complex with 3-isopropylmalate and Mg2+Crystal structure of 3-isopropylmalate dehydrogenase (Saci_0600) from Sulfolobus acidocaldarius complex with 3-isopropylmalate and Mg2+
Structural highlights
FunctionPublication Abstract from PubMedSulfolobus acidocaldarius, a hyperthermoacidophilic archaeon, possesses two beta-decarboxylating dehydrogenase genes, saci_0600 and saci_2375, in its genome, which suggests that it uses these enzymes for three similar reactions in lysine biosynthesis through 2-aminoadipate, leucine biosynthesis, and the tricarboxylic acid cycle. To elucidate their roles, these two genes were expressed in Escherichia coli in the present study and their gene products were characterized. Saci_0600 recognized 3-isopropylmalate as a substrate, but exhibited slight and no activity for homoisocitrate and isocitrate, respectively. Saci_2375 exhibited distinct and similar activities for isocitrate and homoisocitrate, but no detectable activity for 3-isopropylmalate. These results suggest that Saci_0600 is a 3-isopropylmalate dehydrogenase for leucine biosynthesis and Saci_2375 is a dual function enzyme serving as isocitrate-homoisocitrate dehydrogenase. The crystal structure of Saci_0600 was determined as a closed-form complex that binds 3-isopropylmalate and Mg2+, thereby revealing the structural basis for the extreme thermostability and novel-type recognition of the 3-isopropyl moiety of the substrate. Characterization of two beta-decarboxylating dehydrogenases from Sulfolobus acidocaldarius.,Takahashi K, Nakanishi F, Tomita T, Akiyama N, Lassak K, Albers SV, Kuzuyama T, Nishiyama M Extremophiles. 2016 Nov;20(6):843-853. Epub 2016 Sep 2. PMID:27590116[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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