Tam41 also known as MMp37 is a mitochondrial phosphatidate cytidylyltransferase (CDP-DAG synthase)(EC:2.7.7.41) [1, 2] that catalyzes the formation of CDP-diacylglycerol (CDP-DAG) from phosphatidic acid (PA) in the mitochondrial inner membrane. It is required for the biosynthesis of the dimeric phospholipid cardiolipin, which stabilizes supercomplexes of the mitochondrial respiratory chain in the mitochondrial inner membrane. It is suggested that the N-terminal portion of Tam41 may possess the NTase (Nucleotide Transferase) fold, which is consistent with the CDP-DAG synthase function of Tam41 [3, 4]. Furthermore, it has been shown that Tam41/MMP37 proteins possess the NTase fold but they have only one active site carboxylate and thus probably are not able to carry out enzymatic reaction. These potentially non-active members of NTase fold superfamily may bind ATP, hydrolysis of which is necessary for the translocation of proteins through the membrane [2].

1: Characterization of Mmp37p, a Saccharomyces cerevisiae Mitochondrial Matrix Protein with a Role in Mitochondrial Protein Import. Gallas MR, Dienhart MK, Stuart RA, Long RM; Mol Biol Cell. 2006; [Epub ahead of print] PMID:16790493

2: Comprehensive classification of nucleotidyltransferase fold proteins: identification of novel families and their representatives in human. Kuchta K, Knizewski L, Wyrwicz LS, Rychlewski L, Ginalski K; Nucleic Acids Res. 2009; [Epub ahead of print] PMID:19833706

3: The translocator maintenance protein Tam41 is required for mitochondrial cardiolipin biosynthesis. Kutik S, Rissler M, Guan XL, Guiard B, Shui G, Gebert N, Heacock PN, Rehling P, Dowhan W, Wenk MR, Pfanner N, Wiedemann N; J Cell Biol. 2008;183:1213-1221. PMID:19114592

4: Tam41 is a CDP-diacylglycerol synthase required for cardiolipin biosynthesis in mitochondria. Tamura Y, Harada Y, Nishikawa S, Yamano K, Kamiya M, Shiota T, Kuroda T, Kuge O, Sesaki H, Imai K, Tomii K, Endo T; Cell Metab. 2013;17:709-718. PMID:23623749