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Cells Jan 2022Diacylglycerol pyrophosphate (DGPP) is an anionic phospholipid formed in plants, yeast, and parasites under multiple stress stimuli. It is synthesized by the...
Diacylglycerol pyrophosphate (DGPP) is an anionic phospholipid formed in plants, yeast, and parasites under multiple stress stimuli. It is synthesized by the phosphorylation action of phosphatidic acid (PA) kinase on phosphatidic acid, a signaling lipid with multifunctional properties. PA functions in the membrane through the interaction of its negatively charged phosphomonoester headgroup with positively charged proteins and ions. DGPP, like PA, can interact electrostatically via the electrostatic-hydrogen bond switch mechanism but differs from PA in its overall charge and shape. The formation of DGPP from PA alters the physicochemical properties as well as the structural dynamics of the membrane. This potentially impacts the molecular and ionic binding of cationic proteins and ions with the DGPP enriched membrane. However, the results of these important interactions in the stress response and in DGPP's overall intracellular function is unknown. Here, using P MAS NMR, we analyze the effect of the interaction of low DGPP concentrations in model membranes with the peptides KALP23 and WALP23, which are flanked by positively charged Lysine and neutral Tryptophan residues, respectively. Our results show a significant effect of KALP23 on the charge of DGPP as compared to WALP23. There was, however, no significant effect on the charge of the phosphomonoester of DGPP due to the interaction with positively charged lipids, dioleoyl trimethylammonium propane (DOTAP) and dioleoyl ethyl-phosphatidylcholine (EtPC). Divalent calcium and magnesium cations induce deprotonation of the DGPP headgroup but showed no noticeable differences on DGPP's charge. Our results lead to a novel model for DGPP-protein interaction.
Topics: Cations, Divalent; Diphosphates; Glycerol; Lysine; Magnetic Resonance Spectroscopy; Models, Molecular; Peptides; Phosphatidylcholines; Proteins; Static Electricity
PubMed: 35053406
DOI: 10.3390/cells11020290 -
The Journal of Biological Chemistry May 1983[adenine-U-14C]ADP-ribose-agmatine and [adenine-U-14C ))ADP-ribose-histone were synthesized by an NAD:arginine ADP-ribosyltransferase from [14C]NAD and agmatine and...
[adenine-U-14C]ADP-ribose-agmatine and [adenine-U-14C ))ADP-ribose-histone were synthesized by an NAD:arginine ADP-ribosyltransferase from [14C]NAD and agmatine and histone, respectively. The pseudo-first order rate constants for breakdown of the two components either in 0.4 N NaOH or in 0.4 M neutral hydroxylamine were identical. Hydroxylamine treatment of [14C]ADP-ribose-agmatine or [32P]ADP-ribose-histone yielded a single radioactive product which was separated by high pressure liquid chromatography and identified as ADP-ribose-hydroxamate by the formation of a ferric chloride complex. Hydrolysis of ADP-ribose-hydroxamate with snake venom phosphodiesterase resulted in the formation of 5'-AMP, consistent with the presence of a pyrophosphate bond. Incubation of ADP-ribose-[14C]agmatine, synthesized by the ADP-ribosyltransferase from NAD and [14C]agmatine, with 0.4 M neutral hydroxylamine resulted in the release of [14C]agmatine rather than phosphoribosyl[14C]agmatine. In addition, neither NAD nor ADP-ribose reacts with hydroxylamine; i.e. there was no evidence of nucleophilic attack by hydroxylamine at the pyrophosphate bond. The ADP-ribosyl-protein linkage formed by the NAD:arginine ADP-ribosyltransferase is considerably more stable to hydroxylamine than is the ADP-ribose-glutamate bond. The presence of ADP-ribose-arginine and ADP-ribose-glutamate synthesized by the ADP-ribosyltransferase and poly(ADP-ribose) synthetase, respectively, may be the chemical basis for the "hydroxylamine-stable" and "hydroxylamine-labile" bonds described by Hilz (Hilz, H. (1981) Hoppe-Seyler's Z. Physiol. Chem. 362, 1415-1425).
Topics: ADP Ribose Transferases; Adenosine Diphosphate Ribose; Agmatine; Animals; Diphosphates; Drug Stability; Half-Life; Histones; Hydroxides; Hydroxylamine; Hydroxylamines; Nucleoside Diphosphate Sugars; Pentosyltransferases; Phosphodiesterase I; Phosphoric Diester Hydrolases; Poly(ADP-ribose) Polymerases; Turkeys
PubMed: 6304041
DOI: No ID Found -
Purinergic Signalling Jun 2023Conventionally, ATP is considered to be the principal energy source in cells. However, over the last few years, a novel role for ATP as a potent extracellular signaling... (Review)
Review
Conventionally, ATP is considered to be the principal energy source in cells. However, over the last few years, a novel role for ATP as a potent extracellular signaling molecule and the principal source of extracellular pyrophosphate, the main endogenous inhibitor of vascular calcification, has emerged. A large body of evidence suggests that two principal mechanisms are involved in the initiation and progression of ectopic calcification: high phosphate concentration and pyrophosphate deficiency. Pathologic calcification of cardiovascular structures, or vascular calcification, is a feature of several genetic diseases and a common complication of chronic kidney disease, diabetes, and aging. Previous studies have shown that the loss of function of several enzymes and transporters involved in extracellular ATP/pyrophosphate metabolism is associated with vascular calcification. Therefore, pyrophosphate homeostasis should be further studied to facilitate the design of novel therapeutic approaches for ectopic calcification of cardiovascular structures, including strategies to increase pyrophosphate concentrations by targeting the ATP/pyrophosphate metabolism cycle.
Topics: Humans; Diphosphates; Vascular Calcification; Homeostasis; Adenosine Triphosphate
PubMed: 35511317
DOI: 10.1007/s11302-022-09867-1 -
Scientific Reports Apr 2022The solid-state reaction was employed to synthesize CaCuPO by varying the mole ratio between Ca and Cu. The structure and crystallography of the pyrophosphate compounds...
The solid-state reaction was employed to synthesize CaCuPO by varying the mole ratio between Ca and Cu. The structure and crystallography of the pyrophosphate compounds were identified and confirmed by using X-ray diffraction (XRD). The Rietveld refinement method and the extended X-ray absorption fine structure (EXAFS) least-squares fitting technique were also applied to refine the sample crystal structure. The single phases of the obtained CaPO, CaCuPO, and CuPO samples and the mixing phases of the obtained CaCuPO and CaCuPO samples were identified, and then only a single phase of the samples was subjected to structural and dielectrical analyses. The structural results exhibit the tetragonal crystal system with the P4 space group for β-CaPO, the monoclinic crystal system with the P2/c space group for CaCuPO, and the C2/c space group for α-CuPO. The dielectric constant (ε) of the single metal pyrophosphates (CaPO and CuPO) was higher than that of binary metal pyrophosphates (CaCuPO). The image sensor result of the CuPO sample (x = 2.00) illustrated a yellowish-green color, while other compounds (x = 0.50-1.50) presented color tones that changed from blue-green to bluish-green. Raman and Fourier transform infrared (FTIR) spectrophotometers were employed to characterize and confirm the vibrational characteristics of the PO group, which contains the O-P-O radical ([PO]) and the P-O-P bride ([OPO]) and approximate M-O stretching modes. Furthermore, this work reports for the first time that the change in the crystal structure of CaCuPO (i.e., bond angle of P-O-P in PO and distortion phenomena in the M-O octahedral site) are cause the correlation between the structure, chromaticity, and dielectric properties of calcium copper pyrophosphates, CaCuPO.
Topics: Calcium; Calcium Pyrophosphate; Copper; Diphosphates; X-Ray Diffraction
PubMed: 35477985
DOI: 10.1038/s41598-022-11056-4 -
The Plant Journal : For Cell and... Sep 2022The THIAMIN REQUIRING2 (TH2) protein comprising a mitochondrial targeting peptide followed by a transcription enhancement A and a haloacid dehalogenase domain is a...
The THIAMIN REQUIRING2 (TH2) protein comprising a mitochondrial targeting peptide followed by a transcription enhancement A and a haloacid dehalogenase domain is a thiamin monophosphate (TMP) phosphatase in the vitamin B1 biosynthetic pathway. The Arabidopsis th2-3 T-DNA insertion mutant was chlorotic and deficient in thiamin diphosphate (TDP). Complementation assays confirmed that haloacid dehalogenase domain alone was sufficient to rescue the th2-3 mutant. In pTH2:TH2-GFP/th2-3 complemented plants, the TH2-GFP was localized to the cytosol, mitochondrion, and nucleus, indicating that the vitamin B1 biosynthetic pathway extended across multi-subcellular compartments. Engineered TH2-GFP localized to the cytosol, mitochondrion, nucleus, and chloroplast, could complement the th2 mutant. Together, these results highlight the importance of intracellular TMP and thiamin trafficking in vitamin B1 biosynthesis. In an attempt to enhance the production of thiamin, we created various constructs to overexpress TH2-GFP in the cytosol, mitochondrion, chloroplast, and nucleus. Unexpectedly, overexpressing TH2-GFP resulted in an increase rather than a decrease in TMP. While studies on th2 mutants support TH2 as a TMP phosphatase, analyses of TH2-GFP overexpression lines implicating TH2 may also function as a TDP phosphatase in planta. We propose a working model that the TMP/TDP phosphatase activity of TH2 connects TMP, thiamin, and TDP into a metabolic cycle. The TMP phosphatase activity of TH2 is required for TDP biosynthesis, and the TDP phosphatase activity of TH2 may modulate TDP homeostasis in Arabidopsis.
Topics: Arabidopsis; DNA-Binding Proteins; Diphosphates; Homeostasis; Phosphoric Monoester Hydrolases; Thiamine; Thiamine Pyrophosphate
PubMed: 35791282
DOI: 10.1111/tpj.15895 -
Advances in Biological Regulation Jan 2013The diphosphoinositol polyphosphates ("inositol pyrophosphates"; PP-InsPs) regulate many cellular processes in eukaryotes, including stress responses, apoptosis, vesicle... (Review)
Review
The diphosphoinositol polyphosphates ("inositol pyrophosphates"; PP-InsPs) regulate many cellular processes in eukaryotes, including stress responses, apoptosis, vesicle trafficking, cytoskeletal dynamics, exocytosis, telomere maintenance, insulin signaling and neutrophil activation. Thus, the enzymes that control the metabolism of the PP-InsPs serve important cell signaling roles. In order to fully characterize how these enzymes are regulated, we need to determine the atomic-level architecture of their active sites. Only then can we fully appreciate reaction mechanisms and their modes of regulation. In this review, we summarize published information obtained from the structural analysis of a human diphosphoinositol polyphosphate phosphohydrolase (DIPP), and a human diphosphoinositol polyphosphate kinase (PPIP5K). This work includes the analysis of crystal complexes with substrates, products, transition state analogs, and a novel phosphonoacetate substrate analog.
Topics: Acid Anhydride Hydrolases; Catalytic Domain; Diphosphates; Humans; Inositol Phosphates; Molecular Docking Simulation; Phosphonoacetic Acid; Phosphotransferases (Phosphate Group Acceptor); Protein Binding; Protein Structure, Tertiary; Signal Transduction; Substrate Specificity
PubMed: 23107997
DOI: 10.1016/j.jbior.2012.10.002 -
Nefrologia 2018Vascular calcification is a pathology characterized by the deposition of calcium-phosphate in cardiovascular structures, mainly in the form of hydroxyapatite crystals,... (Review)
Review
Vascular calcification is a pathology characterized by the deposition of calcium-phosphate in cardiovascular structures, mainly in the form of hydroxyapatite crystals, resulting in ectopic calcification. It is correlated with increased risk of cardiovascular disease and myocardial infarction in diabetic patients and in those with chronic kidney disease (CKD). Vascular smooth muscle cells are sensitive to changes in inorganic phosphate (Pi) levels. They are able to adapt and modify some of their functions and promote changes which trigger calcification. Pi is regulated by parathyroid hormone and 1,25-dihydroxyvitamin D. Changes in the transport of Pi are the primary factor responsible for the regulation of Pi homeostasis and the calcification process. Synthesis of calcification inhibitors is the main mechanism by which cells are able to prevent vascular calcification. Extracellular pyrophosphate (PPi) is a potent endogenous inhibitor of calcium-phosphate deposition both in vivo and in vitro. Patients with CKD show lower levels of PPi and increased activity of the enzyme alkaline phosphatase. Numerous enzymes implicated in the metabolism of PPi have been associated with vascular calcifications. PPi is synthesized from extracellular ATP by nucleotide pyrophosphatase/phosphodiesterase from extracellular ATP hydrolysis. PPi is hydrolyzed into Pi by tissue-nonspecific alkaline phosphatase. ATP can be hydrolyzed to Pi via the ectonucleoside triphosphate diphosphohydrolase family. All these enzymes must be in balance, thereby preventing calcifications. However, diseases like CKD or diabetes induce alterations in their levels. Administration of PPi could open up new treatment options for these patients.
Topics: Diphosphates; Humans; Renal Insufficiency, Chronic; Vascular Calcification
PubMed: 29137892
DOI: 10.1016/j.nefro.2017.07.005 -
Biochemistry Jun 2022Inositol pyrophosphates are signaling molecules containing at least one phosphoanhydride bond that regulate a wide range of cellular processes in eukaryotes. With a...
Inositol pyrophosphates are signaling molecules containing at least one phosphoanhydride bond that regulate a wide range of cellular processes in eukaryotes. With a cyclic array of phosphate esters and diphosphate groups around -inositol, these molecular messengers possess the highest charge density found in nature. Recent work deciphering inositol pyrophosphate biosynthesis in revealed important functions of these messengers in nutrient sensing, hormone signaling, and plant immunity. However, despite the rapid hydrolysis of these molecules in plant extracts, very little is known about the molecular identity of the phosphohydrolases that convert these messengers back to their inositol polyphosphate precursors. Here, we investigate whether Plant and Fungi Atypical Dual Specificity Phosphatases (PFA-DSP1-5) catalyze inositol pyrophosphate phosphohydrolase activity. We find that recombinant proteins of all five PFA-DSP homologues display phosphohydrolase activity with a high specificity for the 5-β-phosphate of inositol pyrophosphates and only minor activity against the β-phosphates of 4-InsP and 6-InsP. We further show that heterologous expression of PFA-DSP1-5 rescues wortmannin sensitivity and deranged inositol pyrophosphate homeostasis caused by the deficiency of the PFA-DSP-type inositol pyrophosphate phosphohydrolase Siw14 in yeast. Heterologous expression in leaves provided evidence that PFA-DSP1 also displays 5-β-phosphate-specific inositol pyrophosphate phosphohydrolase activity . Our findings lay the biochemical basis and provide the genetic tools to uncover the roles of inositol pyrophosphates in plant physiology and plant development.
Topics: Arabidopsis; Diphosphates; Dual-Specificity Phosphatases; Inositol Phosphates; Saccharomyces cerevisiae
PubMed: 35640071
DOI: 10.1021/acs.biochem.2c00145 -
Proceedings of the Royal Society of... Jun 1974
Topics: Adult; Calcinosis; Collagen; Diagnosis, Differential; Diphosphates; Gout; Hand; Humans; Knee; Male; Middle Aged; Radiography; Uric Acid
PubMed: 4368465
DOI: No ID Found -
Cold Spring Harbor Perspectives in... Feb 2010Bioenergetics is central to our understanding of living systems, yet has attracted relatively little attention in origins of life research. This article focuses on... (Review)
Review
Bioenergetics is central to our understanding of living systems, yet has attracted relatively little attention in origins of life research. This article focuses on energy resources available to drive primitive metabolism and the synthesis of polymers that could be incorporated into molecular systems having properties associated with the living state. The compartmented systems are referred to as protocells, each different from all the rest and representing a kind of natural experiment. The origin of life was marked when a rare few protocells happened to have the ability to capture energy from the environment to initiate catalyzed heterotrophic growth directed by heritable genetic information in the polymers. This article examines potential sources of energy available to protocells, and mechanisms by which the energy could be used to drive polymer synthesis.
Topics: Animals; Catalysis; Diphosphates; Energy Metabolism; Humans; Kinetics; Life; Models, Biological; Origin of Life; Polymers; Sunlight; Thermodynamics
PubMed: 20182625
DOI: 10.1101/cshperspect.a004929