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Microcirculation (New York, N.Y. : 1994) Jan 2018Smooth muscle voltage-gated potassium (Kv) channels are important regulators of microvascular tone and tissue perfusion. Recent studies indicate that Kv1 channels... (Review)
Review
Smooth muscle voltage-gated potassium (Kv) channels are important regulators of microvascular tone and tissue perfusion. Recent studies indicate that Kv1 channels represent a key component of the physiological coupling between coronary blood flow and myocardial oxygen demand. While the mechanisms by which metabolic changes in the heart are transduced to alter coronary Kv1 channel gating and promote vasodilation are unclear, a growing body of evidence underscores a pivotal role of Kv1 channels in sensing the cellular redox status. Here, we discuss current knowledge of mechanisms of Kv channel redox regulation with respect to pyridine nucleotide modulation of Kv1 function via ancillary Kvβ proteins as well as direct modulation of channel activity via reactive oxygen and nitrogen species. We identify areas of additional research to address the integration of regulatory processes under altered physiological and pathophysiological conditions that may reveal insights into novel treatment strategies for conditions in which the matching of coronary blood supply and myocardial oxygen demand is compromised.
Topics: Animals; Coronary Vessels; Humans; Microcirculation; Oxidation-Reduction; Potassium Channels, Voltage-Gated; Pyrimidine Nucleotides; Reactive Nitrogen Species; Reactive Oxygen Species
PubMed: 29110409
DOI: 10.1111/micc.12426 -
Proceedings of the National Academy of... Nov 2019If the genome contains outlier sequences extraordinarily sensitive to environmental agents, these would be sentinels for monitoring personal carcinogen exposure and...
If the genome contains outlier sequences extraordinarily sensitive to environmental agents, these would be sentinels for monitoring personal carcinogen exposure and might drive direct changes in cell physiology rather than acting through rare mutations. New methods, adductSeq and freqSeq, provided statistical resolution to quantify rare lesions at single-base resolution across the genome. Primary human melanocytes, but not fibroblasts, carried spontaneous apurinic sites and TG sequence lesions more frequent than ultraviolet (UV)-induced cyclobutane pyrimidine dimers (CPDs). UV exposure revealed hyperhotspots acquiring CPDs up to 170-fold more frequently than the genomic average; these sites were more prevalent in melanocytes. Hyperhotspots were disproportionately located near genes, particularly for RNA-binding proteins, with the most-recurrent hyperhotspots at a fixed position within 2 motifs. One motif occurs at ETS family transcription factor binding sites, known to be UV targets and now shown to be among the most sensitive in the genome, and at sites of mTOR/5' terminal oligopyrimidine-tract translation regulation. The second occurs at ATTCTY, which developed "dark CPDs" long after UV exposure, repaired CPDs slowly, and had accumulated CPDs prior to the experiment. Motif locations active as hyperhotspots differed between cell types. Melanocyte CPD hyperhotspots aligned precisely with recurrent UV signature mutations in individual gene promoters of melanomas and with known cancer drivers. At sunburn levels of UV exposure, every cell would have a hyperhotspot CPD in each of the ∼20 targeted cell pathways, letting hyperhotspots act as epigenetic marks that create phenome instability; high prevalence favors cooccurring mutations, which would allow tumor evolution to use weak drivers.
Topics: 5' Untranslated Regions; Cells, Cultured; DNA Damage; Fibroblasts; Gene Expression Regulation; Genome, Human; High-Throughput Nucleotide Sequencing; Humans; Melanocytes; Melanoma; Mutation; Promoter Regions, Genetic; Protein Biosynthesis; Pyrimidine Dimers; Pyrimidine Nucleotides; Skin Neoplasms; TOR Serine-Threonine Kinases; Ultraviolet Rays
PubMed: 31723047
DOI: 10.1073/pnas.1907860116 -
Ciencia & Saude Coletiva Aug 2022The development of new drugs depends on several scientific steps, which culminate in clinical trials. The clinical trials pharmacy (CTP) is the place for receiving,... (Review)
Review
The development of new drugs depends on several scientific steps, which culminate in clinical trials. The clinical trials pharmacy (CTP) is the place for receiving, preparing, storing and dispensing the investigational product or study drug. Therefore, it must have infrastructure and procedures that guarantee participant safety and quality of research data. This study aimed to systematize guidelines for CTP in Brazil. We conducted a scope review and organized the results using the Ishikawa Method (6Ms). In total, 51 publications were selected for each "M", 39 laws, regulations or guidelines and 12 scientific articles: 25 publications for pharmaceutical services (pharmacy procedures to ensure participant safety from investigational product ordering to final disposition), 14 for Quality Indicators, 12 for Human Resources, 11 for Infrastructure, 11 for Material Resources and 5 for Investigational Product. Our results synthesize information for the organization, operation and evaluation of CTP in Brazil, emphasizes the inclusion of the pharmacist within the clinical trials context, and contributes to preparation for monitoring, auditing, and inspections conducted by regulatory agencies.
Topics: Brazil; Cytidine Triphosphate; Humans; Pharmaceutical Services; Pharmacies; Pharmacists
PubMed: 35894322
DOI: 10.1590/1413-81232022278.04052022 -
Chembiochem : a European Journal of... Jan 2022High costs and low availability of UDP-galactose hampers the enzymatic synthesis of valuable oligosaccharides such as human milk oligosaccharides. Here, we report the...
High costs and low availability of UDP-galactose hampers the enzymatic synthesis of valuable oligosaccharides such as human milk oligosaccharides. Here, we report the development of a platform for the scalable, biocatalytic synthesis and purification of UDP-galactose. UDP-galactose was produced with a titer of 48 mM (27.2 g/L) in a small-scale batch process (200 μL) within 24 h using 0.02 g /g . Through in-situ ATP regeneration, the amount of ATP (0.6 mM) supplemented was around 240-fold lower than the stoichiometric equivalent required to achieve the final product yield. Chromatographic purification using porous graphic carbon adsorbent yielded UDP-galactose with a purity of 92 %. The synthesis was transferred to 1 L preparative scale production in a stirred tank bioreactor. To further reduce the synthesis costs here, the supernatant of cell lysates was used bypassing expensive purification of enzymes. Here, 23.4 g/L UDP-galactose were produced within 23 h with a synthesis yield of 71 % and a biocatalyst load of 0.05 g /g . The costs for substrates per gram of UDP-galactose synthesized were around 0.26 €/g.
Topics: Adenosine Triphosphate; Bioreactors; Cell-Free System; Enzymes; Hydrogen-Ion Concentration; Oligosaccharides; Proof of Concept Study; Uridine Diphosphate Galactose
PubMed: 34637168
DOI: 10.1002/cbic.202100361 -
Journal of the American Chemical Society Feb 2024Complex bacterial glycoconjugates drive interactions between pathogens, symbionts, and their human hosts. Glycoconjugate biosynthesis is initiated at the membrane...
Complex bacterial glycoconjugates drive interactions between pathogens, symbionts, and their human hosts. Glycoconjugate biosynthesis is initiated at the membrane interface by phosphoglycosyl transferases (PGTs), which catalyze the transfer of a phosphosugar from a soluble uridine diphosphosugar (UDP-sugar) substrate to a membrane-bound polyprenol-phosphate (Pren-P). The two distinct superfamilies of PGT enzymes (polytopic and monotopic) show striking differences in their structure and mechanism. We designed and synthesized a series of uridine bisphosphonates (UBPs), wherein the diphosphate of the UDP and UDP-sugar is replaced by a substituted methylene bisphosphonate (CXY-BPs; X/Y = F/F, Cl/Cl, ()-H/F, ()-H/F, H/H, CH/CH). UBPs and UBPs incorporating an -acetylglucosamine (GlcNAc) substituent at the β-phosphonate were evaluated as inhibitors of a polytopic PGT (WecA from ) and a monotopic PGT (PglC from ). Although CHF-BP most closely mimics diphosphate with respect to its acid/base properties, the less basic CF-BP conjugate more strongly inhibited PglC, whereas the more basic CH-BP analogue was the strongest inhibitor of WecA. These surprising differences indicate different modes of ligand binding for the different PGT superfamilies, implicating a modified P-O interaction with the structural Mg. For the monoPGT enzyme, the two diastereomeric CHF-BP conjugates, which feature a chiral center at the P-CHF-P carbon, also exhibited strikingly different binding affinities and the inclusion of GlcNAc with the native α-anomer configuration significantly improved binding affinity. UBP-sugars are thus revealed as informative new mechanistic probes of PGTs that may aid development of novel antibiotic agents for the exclusively prokaryotic monoPGT superfamily.
Topics: Humans; Transferases; Uridine; Diphosphates; Glycoconjugates; Diphosphonates; Sugars; Uridine Diphosphate
PubMed: 38271668
DOI: 10.1021/jacs.3c11402 -
Blood Advances Mar 2024Adult T-cell leukemia/lymphoma (ATL) is triggered by infection with human T-cell lymphotropic virus-1 (HTLV-1). Here, we describe the reprogramming of pyrimidine...
Adult T-cell leukemia/lymphoma (ATL) is triggered by infection with human T-cell lymphotropic virus-1 (HTLV-1). Here, we describe the reprogramming of pyrimidine biosynthesis in both normal T cells and ATL cells through regulation of uridine-cytidine kinase 2 (UCK2), which supports vigorous proliferation. UCK2 catalyzes the monophosphorylation of cytidine/uridine and their analogues during pyrimidine biosynthesis and drug metabolism. We found that UCK2 was overexpressed aberrantly in HTLV-1-infected T cells but not in normal T cells. T-cell activation via T-cell receptor (TCR) signaling induced expression of UCK2 in normal T cells. Somatic alterations and epigenetic modifications in ATL cells activate TCR signaling. Therefore, we believe that expression of UCK2 in HTLV-1-infected cells is induced by dysregulated TCR signaling. Recently, we established azacitidine-resistant (AZA-R) cells showing absent expression of UCK2. AZA-R cells proliferated normally in vitro, whereas UCK2 knockdown inhibited ATL cell growth. Although uridine and cytidine accumulated in AZA-R cells, possibly because of dysfunction of pyrimidine salvage biosynthesis induced by loss of UCK2 expression, the amount of UTP and CTP was almost the same as in parental cells. Furthermore, AZA-R cells were more susceptible to an inhibitor of dihydroorotic acid dehydrogenase, which performs the rate-limiting enzyme of de novo pyrimidine nucleotide biosynthesis, and more resistant to dipyridamole, an inhibitor of pyrimidine salvage biosynthesis, suggesting that AZA-R cells adapt to UCK2 loss by increasing de novo pyrimidine nucleotide biosynthesis. Taken together, the data suggest that fine-tuning pyrimidine biosynthesis supports vigorous cell proliferation of both normal T cells and ATL cells.
Topics: Adult; Humans; Pyrimidines; Uridine; Cell Proliferation; Cytidine; Human T-lymphotropic virus 1; Pyrimidine Nucleotides; Receptors, Antigen, T-Cell; T-Lymphocytes
PubMed: 38190613
DOI: 10.1182/bloodadvances.2023011131 -
Acta Crystallographica. Section F,... Apr 2020Human O-phosphoethanolamine phospho-lyase (hEtnppl; EC 4.2.3.2) is a pyridoxal 5'-phosphate-dependent enzyme that catalyzes the degradation of O-phosphoethanolamine...
Human O-phosphoethanolamine phospho-lyase (hEtnppl; EC 4.2.3.2) is a pyridoxal 5'-phosphate-dependent enzyme that catalyzes the degradation of O-phosphoethanolamine (PEA) into acetaldehyde, phosphate and ammonia. Physiologically, the enzyme is involved in phospholipid metabolism, as PEA is the precursor of phosphatidylethanolamine in the CDP-ethanolamine (Kennedy) pathway. Here, the crystal structure of hEtnppl in complex with pyridoxamine 5'-phosphate was determined at 2.05 Å resolution by molecular replacement using the structure of A1RDF1 from Arthrobacter aurescens TC1 (PDB entry 5g4i) as the search model. Structural analysis reveals that the two proteins share the same general fold and a similar arrangement of active-site residues. These results provide novel and useful information for the complete characterization of the human enzyme.
Topics: Carbon-Oxygen Lyases; Catalytic Domain; Crystallography, X-Ray; Cytidine Diphosphate; Ethanolamines; Humans; Models, Molecular; Protein Structure, Quaternary; Pyridoxal Phosphate
PubMed: 32254049
DOI: 10.1107/S2053230X20002988 -
Applied Microbiology and Biotechnology Aug 2020Polyphosphosphate kinases (PPKs) catalyse the reversible transfer of the γ-phosphate group of a nucleoside-triphosphate to a growing chain of polyphosphate. Most known...
Polyphosphosphate kinases (PPKs) catalyse the reversible transfer of the γ-phosphate group of a nucleoside-triphosphate to a growing chain of polyphosphate. Most known PPKs are specific for ATP, but some can also use GTP as a phosphate donor. In this study, we describe the properties of a PPK2-type PPK of the β-proteobacterium Ralstonia eutropha. The purified enzyme (PPK2c) is highly unspecific and accepts purine nucleotides as well as the pyridine nucleotides including UTP as substrates. The presence of a polyP primer is not necessary for activity. The corresponding nucleoside diphosphates and microscopically detectable polyphosphate granules were identified as reaction products. PPK2c also catalyses the formation of ATP, GTP, CTP, dTTP and UTP from the corresponding nucleoside diphosphates, if polyP is present as a phosphate donor. Remarkably, the nucleoside-tetraphosphates AT(4)P, GT(4)P, CT(4)P, dTT(4)P and UT(4)P were also detected in substantial amounts. The low nucleotide specificity of PPK2c predestines this enzyme in combination with polyP to become a powerful tool for the regeneration of ATP and other nucleotides in biotechnological applications. As an example, PPK2c and polyP were used to replace ATP and to fuel the hexokinase-catalysed phosphorylation of glucose with only catalytic amounts of ADP. KEY POINTS: • PPK2c of R. eutropha can be used for regeneration of any NTP or dNTP. • PPK2c is highly unspecific and accepts all purine and pyrimidine nucleotides. • PPK2c forms polyphosphate granules in vitro from any NTP.
Topics: Adenosine Diphosphate; Adenosine Triphosphate; Cupriavidus necator; Escherichia coli; Phosphorylation; Phosphotransferases (Phosphate Group Acceptor); Purine Nucleotides; Pyrimidine Nucleotides; Uridine Diphosphate
PubMed: 32500270
DOI: 10.1007/s00253-020-10706-9 -
Cell Nov 2021Cyclic pyrimidines cCMP and cUMP were known to be present in a variety of organisms and cell types, but their biological roles remained mysterious. Tal et al. show that...
Cyclic pyrimidines cCMP and cUMP were known to be present in a variety of organisms and cell types, but their biological roles remained mysterious. Tal et al. show that bacteria use cCMP and cUMP as second messengers that function in anti-phage defense.
Topics: Bacteriophages; Cyclic CMP; Nucleotides, Cyclic; Pyrimidines; Second Messenger Systems
PubMed: 34767773
DOI: 10.1016/j.cell.2021.10.012 -
Database : the Journal of Biological... Nov 2021Protein domains are functional and structural units of proteins. They are responsible for a particular function that contributes to protein's overall role. Because of...
Protein domains are functional and structural units of proteins. They are responsible for a particular function that contributes to protein's overall role. Because of this essential role, the majority of the genetic variants occur in the domains. In this study, the somatic mutations across 21 cancer types were mapped to the individual protein domains. To map the mutations to the domains, we employed the whole human proteome to predict the domains in each protein sequence and recognized about 149 668 domains. A novel Perl-API program was developed to convert the protein domain positions into genomic positions, and users can freely access them through GitHub. We determined the distribution of protein domains across 23 chromosomes with the help of these genomic positions. Interestingly, chromosome 19 has more number of protein domains in comparison with other chromosomes. Then, we mapped the cancer mutations to all the protein domains. Around 46-65% of mutations were mapped to their corresponding protein domains, and significantly mutated domains for all the cancer types were determined using the local false discovery ratio (locfdr). The chromosome positions for all the protein domains can be verified using the cross-reference ensemble database. Database URL: https://dcmp.vit.ac.in/.
Topics: Deoxycytidine Monophosphate; Humans; Mutant Proteins; Neoplasms; Protein Domains; Proteome
PubMed: 34791106
DOI: 10.1093/database/baab066