The CDP-alcohol phosphotransferase (CDP-AP) family of integral membrane enzymes catalyses the transfer of a substituted phosphate group from a CDP-linked donor to an alcohol acceptor. This is an essential reaction for phospholipid biosynthesis across all kingdoms of life, and it is catalysed solely by CDP-APs. Here we report the 2.0 Å resolution crystal structure of a representative CDP-AP from Archaeoglobus fulgidus. The enzyme (AF2299) is a homodimer, with each protomer consisting of six transmembrane helices and an N-terminal cytosolic domain. A polar cavity within the membrane accommodates the active site, lined with the residues from an absolutely conserved CDP-AP signature motif (D(1)xxD(2)G(1)xxAR...G(2)xxxD(3)xxxD(4)). Structures in the apo, CMP-bound, CDP-bound and CDP-glycerol-bound states define functional roles for each of these eight conserved residues and allow us to propose a sequential, base-catalysed mechanism universal for CDP-APs, in which the fourth aspartate (D4) acts as the catalytic base.
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http://dx.doi.org/10.1038/ncomms5068 | DOI Listing |
Nat Commun
January 2025
Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
Phospholipids are the most abundant component in lipid membranes and are essential for the structural and functional integrity of the cell. In eukaryotic cells, phospholipids are primarily synthesized de novo through the Kennedy pathway that involves multiple enzymatic processes. The terminal reaction is mediated by a group of cytidine-5'-diphosphate (CDP)-choline /CDP-ethanolamine-phosphotransferases (CPT/EPT) that use 1,2-diacylglycerol (DAG) and CDP-choline or CDP-ethanolamine to produce phosphatidylcholine (PC) or phosphatidylethanolamine (PE) that are the main phospholipids in eukaryotic cells.
View Article and Find Full Text PDFArch Biochem Biophys
October 2022
Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, 96813, USA. Electronic address:
Selenoprotein I (selenoi) is a unique selenocysteine (Sec)-containing protein widely expressed throughout the body. Selenoi belongs to two different protein families: the selenoproteins that are characterized by a redox reactive Sec residue and the lipid phosphotransferases that contain the highly conserved cytidine diphosphate (CDP)-alcohol phosphotransferase motif. Selenoi catalyzes the third reaction of the CDP-ethanolamine branch of the Kennedy pathway within the endoplasmic reticulum membrane.
View Article and Find Full Text PDFFront Cell Infect Microbiol
January 2022
Department of Microbiology, University of Tennessee Knoxville, Knoxville, TN, United States.
The fungal phosphatidylserine (PS) synthase, a membrane protein encoded by the gene, is a potential drug target for pathogenic fungi, such as . However, both substrate-binding sites of Cho1 have not been characterized. Cho1 has two substrates: cytidyldiphosphate-diacylglycerol (CDP-DAG) and serine.
View Article and Find Full Text PDFJ Mol Biol
August 2020
Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA. Electronic address:
In mycobacteria, phosphatidylinositol (PI) acts as a common lipid anchor for key components of the cell wall, including the glycolipids phosphatidylinositol mannoside, lipomannan, and lipoarabinomannan. Glycolipids in Mycobacterium tuberculosis, the causative agent of tuberculosis, are important virulence factors that modulate the host immune response. The identity-defining step in PI biosynthesis in prokaryotes, unique to mycobacteria and few other bacterial species, is the reaction between cytidine diphosphate-diacylglycerol and inositol-phosphate to yield phosphatidylinositol-phosphate, the immediate precursor to PI.
View Article and Find Full Text PDFCommun Biol
April 2020
Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16 C, SE-106 91 Stockholm, Sweden.
Tuberculosis causes over one million yearly deaths, and drug resistance is rapidly developing. phosphatidylinositol phosphate synthase (PgsA1) is an integral membrane enzyme involved in biosynthesis of inositol-derived phospholipids required for formation of the mycobacterial cell wall, and a potential drug target. Here we present three crystal structures of PgsA1: in absence of substrates (2.
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