Protonation induces base rotation of purine nucleotides pdGuo and pGuo

2016 ◽  
Vol 18 (22) ◽  
pp. 15081-15090 ◽  
Author(s):  
R. R. Wu ◽  
C. C. He ◽  
L. A. Hamlow ◽  
Y.-w. Nei ◽  
G. Berden ◽  
...  
Keyword(s):  
Guanine Nucleotides ◽  
Purine Nucleotides ◽  
Irmpd Spectroscopy ◽  
Sugar Puckering ◽  
Base Orientation

Synergistic IRMPD spectroscopy and computations find that protonation of the guanine nucleotides (pdGuo and pGuo) occurs preferentially at N7 and induces changes in the base orientation and sugar puckering.

scholarly journals Purine salvage networks in Giardia lamblia.

1983 ◽  
Vol 158 (5) ◽  
pp. 1703-1712 ◽  
Author(s):  
C C Wang ◽  
S Aldritt
Keyword(s):  
Giardia Lamblia ◽  
De Novo ◽  
Adenine Nucleotides ◽  
Guanine Nucleotides ◽  
Rational Approach ◽  
Purine Nucleotides ◽  
Purine Salvage ◽  
Nucleotide Synthesis ◽  
Guanine Base

Purine metabolism in Giardia lamblia was investigated by monitoring incorporation of radiolabeled precursors into purine nucleotides in the log-phase trophozoites cultivated in vitro in axenic media and incubated in buffered saline glucose. The lack of incorporation of formate, glycine, hypoxanthine, inosine, and xanthine into the nucleotide pool suggests the absence of de novo purine nucleotide synthesis and the inability to form IMP as the precursor of AMP and GMP in G. lamblia. Only adenine, adenosine, guanine, and guanosine were incorporated. Further analysis of the labeled nucleotides by HPLC indicated that adenine and adenosine are converted only to adenine nucleotides whereas guanine and guanosine are only incorporated into guanine nucleotides. There is no competition of incorporation between adenine/adenosine and guanine/guanosine, and there is no interconversion between adenine and guanine nucleotides. Results from analyzing [5'-3H]guanosine incorporation indicate that the ribose moiety is not incorporated with the guanine base. Assays of purine salvage enzymic activities in the crude extracts of G. lamblia revealed the presence of only four major enzymes; adenosine and guanosine hydrolases and adenine and guanine phosphoribosyl transferases. Apparently, G. lamblia has an exceedingly simple purine salvage system; it converts adenosine and guanosine to corresponding purine bases and then forms AMP and GMP by the actions of corresponding purine phosphoribosyl transferases. The guanine phosphoribosyl transferase in G. lamblia is interesting because it does not recognize either hypoxanthine or xanthine as substrate. It thus must have a unique substrate specificity and may be regarded as a potential target to attack as a rational approach to chemotherapeutic control of giardiasis.

scholarly journals Synthesis of ribonucleic acid in purine-deficient Escherichia coli and a comparison with the effects of amino acid starvation

1970 ◽  
Vol 120 (1) ◽  
pp. 125-132 ◽  
Author(s):  
N. F. Varney ◽  
Gillian A. Thomas ◽  
K. Burton
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Rna Polymerase ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Adenine Nucleotides ◽  
Amino Acid Starvation ◽  
Guanine Nucleotides ◽  
Purine Nucleotides ◽  
Acid Control

1. Experiments with rifampicin and stringent strains of Escherichia coli (pro−purB−rel+) indicate that purine deficiency does not decrease and may considerably increase the potential for RNA synthesis by RNA polymerase molecules that are bound to DNA and have already commenced transcription. 2. DNA–RNA hybridization experiments indicate that purine starvation increases the distribution of bound RNA polymerase molecules between the cistrons for mRNA and those for stable RNA. 3. Synthesis of β-galactosidase mRNA is more dependent on the ability to synthesize guanine nucleotides than on the ability to synthesize adenine nucleotides. 4. Amino acid starvation tends to decrease the potential for RNA synthesis by RNA polymerase molecules bound to DNA. 5. Since this effect differs from that due to purine starvation, amino acid control of RNA synthesis does not appear to operate solely by causing a deficiency of purine nucleotides. 6. The results are discussed in terms of the ability to initiate RNA chains and to extend them under different circumstances.

Recovery of nucleotide levels after cell injury

1981 ◽  
Vol 59 (2) ◽  
pp. 116-121 ◽  
Author(s):  
C. Terry Warnick ◽  
Harrison M. Lazarus
Keyword(s):  
Cell Injury ◽  
Energy Charge ◽  
Mouse Kidney ◽  
Guanine Nucleotides ◽  
Kidney Cells ◽  
Purine Nucleotides ◽  
Major Pathway ◽  
Purine Catabolism ◽  
Injured Kidney

The major pathway of purine catabolism in mouse kidney during ischemia occurs through IMP, inosine, hypoxanthine, and xanthine. Short periods of ischemia (reversible cell injury) allow a rapid return of the energy charge to control values and a rapid return of ATP and GTP to values of 60–70% of control ATP and GTP then slowly return to control levels over the next 24 h. Long periods of ischemia (irreversible cell injury; ischemic times longer than 1 h) allow a gradual return of the energy charge to control levels. ATP, GTP, or total adenine or guanine nucleotides do not return to control levels even after 24 h of reinfusion under these circumstances. We conclude that irreversibly injured kidney cells retain the ability to phosphorylate purine nucleotides, but lose the ability to restore the concentrations of the purine nucleotides to control values.

Purine 3′:5′-cyclic nucleotides with the nucleobase in asynorientation: cAMP, cGMP and cIMP

2016 ◽  
Vol 72 (6) ◽  
pp. 465-479 ◽  
Author(s):  
Katarzyna Anna Ślepokura
Keyword(s):  
Cyclic Nucleotides ◽  
Three Dimensional ◽  
Purine Nucleotides ◽  
Conformational Preferences ◽  
Cellular Signal ◽  
Structural Database ◽  
Cyclic Phosphate ◽  
Base Orientation ◽  
Chemical Groups ◽  
Made In

Purine 3′:5′-cyclic nucleotides are very well known for their role as the secondary messengers in hormone action and cellular signal transduction. Nonetheless, their solid-state conformational details still require investigation. Five crystals containing purine 3′:5′-cyclic nucleotides have been obtained and structurally characterized, namely adenosine 3′:5′-cyclic phosphate dihydrate, C10H12N5O6P·2H2O or cAMP·2H2O, (I), adenosine 3′:5′-cyclic phosphate 0.3-hydrate, C10H12N5O6P·0.3H2O or cAMP·0.3H2O, (II), guanosine 3′:5′-cyclic phosphate pentahydrate, C10H12N5O7P·5H2O or cGMP·5H2O, (III), sodium guanosine 3′:5′-cyclic phosphate tetrahydrate, Na+·C10H11N5O7P−·4H2O or Na(cGMP)·4H2O, (IV), and sodium inosine 3′:5′-cyclic phosphate tetrahydrate, Na+·C10H10N4O7P−·4H2O or Na(cIMP)·4H2O, (V). Most of the cyclic nucleotide zwitterions/anions [two from four cAMP present in total in (I) and (II), cGMP in (III), cGMP−in (IV) and cIMP−in (V)] aresynconformers about the N-glycosidic bond, and this nucleobase arrangement is accompanied by Crib—H...Npurhydrogen bonds (rib = ribose and pur = purine). The base orientation is tuned by the ribose pucker. An analysis of data obtained from the Cambridge Structural Database made in the context ofsyn–anticonformational preferences has revealed that among thesynconformers of various purine nucleotides, cyclic nucleotides and dinucleotides predominate significantly. The interactions stabilizing thesynconformation have been indicated. The inter-nucleotide contacts in (I)–(V) have been systematized in terms of the chemical groups involved. All five structures display three-dimensional hydrogen-bonded networks.

The Role of Purinergic Signaling in Trichomonas vaginalis Infection

2020 ◽  
Vol 20 ◽  
Author(s):  
Micheli Ferla ◽  
Tiana Tasca
Keyword(s):  
Drug Targets ◽  
Trichomonas Vaginalis ◽  
Hiv Transmission ◽  
Cell Damage ◽  
Purinergic Signaling ◽  
Host Cells ◽  
Purine Nucleotides ◽  
Cellular Effects ◽  
Adverse Pregnancy ◽  
Purine Salvage Pathways

: Trichomoniasis, one of the most common non-viral sexually transmitted infections worldwide, is caused by the parasite Trichomonas vaginalis. The pathogen colonizes the human urogenital tract and the infection is associated with complications such as adverse pregnancy outcomes, cervical cancer, and an increase in HIV transmission. The mecha-nisms of pathogenicity are multifactorial, and controlling immune responses is essential for infection maintenance. Extra-cellular purine nucleotides are released by cells in physiological and pathological conditions, and they are hydrolyzed by enzymes called ecto-nucleotidases. The cellular effects of nucleotides and nucleosides occur via binding to purinoceptors, or throughthe uptake by nucleoside transporters. Altogether, enzymes, receptors and transporters constitute the purinergic signaling, a cellular network that regulates several effects in practically all systems including mammals, helminths, proto-zoa, bacteria, and fungi. In this context, this review updates the data on purinergic signaling involved in T. vaginalis biol-ogy and interaction with host cells, focusing on the characterization of ecto-nucleotidases and on purine salvage pathways. The implications of the final products, the nucleosides adenosine and guanosine, for human neutrophil response and vagi-nal epithelial cell damage reveal the purinergic signaling as a potential new mechanism for alternative drug targets.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

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