Keisuke Kimura, Fumihiro Kawai, Hisako Kubota-Kawai, Yasunori Watanabe, Kentaro Tomii, Rieko Kojima, Kunio Hirata, Yu Yamamori, Toshiya Endo, Yasushi Tamura
Journal of biochemistry 2022 Mar 31Translocator assembly and maintenance 41 (Tam41) catalyses the synthesis of cytidine diphosphate diacylglycerol (CDP-DAG), which is a high-energy intermediate phospholipid critical for generating cardiolipin in mitochondria. Although Tam41 is present almost exclusively in eukaryotic cells, a Firmicutes bacterium contains the gene encoding Tam41-type CDP-DAG synthase (FbTam41). FbTam41 converted phosphatidic acid (PA) to CDP-DAG using a ternary complex mechanism in vitro. Additionally, FbTam41 functionally substituted yeast Tam41 in vivo. These results demonstrate that Tam41-type CDP-DAG synthase functions in some prokaryotic cells. We determined the crystal structure of FbTam41 lacking the C-terminal 18 residues in the cytidine triphosphate (CTP)-Mg2+ bound form at a resolution of 2.6 Å. The crystal structure showed that FbTam41 contained a positively charged pocket that specifically accommodated CTP-Mg2+ and PA in close proximity. By using this structure, we constructed a model for the full-length structure of FbTam41 containing the last a-helix, which was missing in the crystal structure. Based on this model, we propose a molecular mechanism for CDP-DAG synthesis in bacterial cells and mitochondria. © The Author(s) 2022. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
Keisuke Kimura, Fumihiro Kawai, Hisako Kubota-Kawai, Yasunori Watanabe, Kentaro Tomii, Rieko Kojima, Kunio Hirata, Yu Yamamori, Toshiya Endo, Yasushi Tamura. Crystal structure of Tam41 cytidine diphosphate diacylglycerol synthase from a Firmicutes bacterium. Journal of biochemistry. 2022 Mar 31;171(4):429-441
PMID: 34964897
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