Download MendeleyStructure and mechanism of an intramembrane liponucleotide synthetase central for phospholipid biosynthesis
Liu, X., Yin, Y., Wu, J., Liu, Z.(2014) Nat Commun 5: 4244-4244
- PubMed: 24968740
- DOI: https://doi.org/10.1038/ncomms5244
- Primary Citation of Related Structures:
4Q2E, 4Q2G - PubMed Abstract:
Phospholipids are elemental building-block molecules for biological membranes. Biosynthesis of phosphatidylinositol, phosphatidylglycerol and phosphatidylserine requires a central liponucleotide intermediate named cytidine-diphosphate diacylglycerol (CDP-DAG). The CDP-DAG synthetase (Cds) is an integral membrane enzyme catalysing the formation of CDP-DAG, an essential step for phosphoinositide recycling during signal transduction. Here we report the structure of the Cds from Thermotoga maritima (TmCdsA) at 3.4 Å resolution. TmCdsA forms a homodimer and each monomer contains nine transmembrane helices arranged into a novel fold with three domains. An unusual funnel-shaped cavity penetrates half way into the membrane, allowing the enzyme to simultaneously accept hydrophilic substrate (cytidine 5'-triphosphate (CTP)/deoxy-CTP) from cytoplasm and hydrophobic substrate (phosphatidic acid) from membrane. Located at the bottom of the cavity, a Mg(2+)-K(+) hetero-di-metal centre coordinated by an Asp-Asp dyad serves as the cofactor of TmCdsA. The results suggest a two-metal-ion catalytic mechanism for the Cds-mediated synthesis of CDP-DAG at the membrane-cytoplasm interface.
Organizational Affiliation:
1] National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China [2].
