Preparation of analogues of cytosine and 2-pyrimidinone nucleosides and their effect on bacterial (Escherichia coli A 19) cytidine aminohydrolase

1985 ◽  
Vol 50 (2) ◽  
pp. 393-417 ◽  
Author(s):  
Antonín Holý ◽  
Anita Ludziša ◽  
Ivan Votruba ◽  
Kateřina Šedivá ◽  
Helmut Pischel
Keyword(s):  
Hydroxy Group ◽  
Necessary Conditions ◽  
Heterocyclic System ◽  
Similar Type ◽  
Open Chain ◽  
Heterocyclic Base ◽  
Basic Character ◽  
E Coli ◽  
Sugar Moiety ◽  
Derivatives Of

The set of compounds investigated as substrates and inhibitors of bacterial cytidine aminohydrolase (EC 3.5.4.5) consists of cytidine analogues modified in the heterocyclic base or the sugar moiety and analogues of the similar type derived from l-(β-D-ribofuranosyl)-2-pyrimidone (I) and its isomers. The latter group of compounds includes also open-chain derivatives of neutral and acidic character. These compounds were prepared by novel synthetic procedures. Minimum necessary conditions for the structure of an inhibitor of cytidine aminohydrolase from E. coli A 19 include: a heterocyclic system containing an Rf-N-CO-N(H) fragment of a basic character in which Rf denotes a β-D-aldopentafuranoside with a 3-hydroxy group of ribo-configuration; the 5-hydroxy group of the sugar moiety may bear a substituent, except a phosphomonoester function. The heterocyclic base may also bear substituents in positions other than α to the nucleoside bond which do not reduce substantially the basicity of the system and do not change the conformation of the nucleoside molecule.

The effect of acceptor modification upon the synthesis of dinucleoside phosphates catalyzed by non-specific ribonucleases of Penicillium claviforme

1979 ◽  
Vol 44 (2) ◽  
pp. 613-625 ◽  
Author(s):  
Valentina I. Gulyaeva ◽  
Antonín Holý
Keyword(s):  
Reaction Center ◽  
Hydroxy Group ◽  
Pyrimidine Ring ◽  
Phosphate Group ◽  
Mutual Orientation ◽  
Acceptor Molecule ◽  
Heterocyclic Base ◽  
Sugar Moiety ◽  
Cyclic Phosphate ◽  
Penicillium Claviforme

The present paper studies the effect of the modification of heterocyclic base, sugar moiety and the presence of phosphate group on the nucleoside acceptors in the synthesis of dinucleoside phosphates from adenosine 2',3'-cyclic phosphate as donor, catalyzed by nonspecific acidic extracellular and intracellular ribonucleases from Penicillium claviforme. The enzyme binds specifically the acceptor molecule, preferring cytosine nucleosides. It requires the presence of the whole sugar moiety, an exact mutual orientation of the heterocyclic base and the reaction center (5'-hydroxy group), and a suitable conformation of the acceptor molecule. The enzyme-acceptor bond is homochiral and the presence of the N3-H group in the pyrimidine ring is important. The reaction between the donor and the acceptor is bimolecular and is competitively inhibited by some purine nucleosides.

Preparation, antibacterial effects and enzymatic degradation of 5-fluorouracil nucleosides

1980 ◽  
Vol 45 (11) ◽  
pp. 3217-3230 ◽  
Author(s):  
Beatrice Schwarz ◽  
Dieter Cech ◽  
Antonín Holý ◽  
Jan Škoda
Keyword(s):  
Enzymatic Degradation ◽  
Allyl Bromide ◽  
Antibacterial Effect ◽  
Structural Features ◽  
Enzymatic Cleavage ◽  
Cell Free Extract ◽  
Antibacterial Effects ◽  
E Coli ◽  
Sugar Moiety ◽  
Derivatives Of

Reaction of perbenzoylated aldopentafuranosyl derivatives of uracil with fluorine in acetic acid afforded perbenzoylated 5-fluorouracil nucleosides. Their methanolysis gave the following free nucleosides of 5-fluorouracil: β-D-ribofuranoside (Id), 2-deoxy-β-D-ribofuranoside (IId), their enantiomers VIII and IX, α-D-ribofuranoside (XIII), 2-deoxy-α-D-ribofuranoside (XV), β-D-arabinofuranoside (IV) and its L-enantiomer X, β-D-xylofuranoside (V) and its α-D-anomer XI, α-L-lyxofuranoside (VI) and 2-deoxy-α-L-lyxofuranoside (VII) and the enantiomers of the latter two compounds, XII and XIV, respectively. Analogously were obtained 5-deoxy-β-D-ribofuranoside (III), β-D-ribopyranoside (XVI) and 1-(S)-(2,3-dihydroxypropyl)-5-fluorouracil (XVIIc). 1-Allyl-5-fluorouracil (XVIII) was prepared by reaction of allyl bromide with 2,4-bis(trimethylsilyloxy)-5-fluoropyrimidine. The cell-free extract from Escherichia coli cleaves all the 5-fluorouracil nucleosides in which the nucleoside carbon atom has the R-configuration and the 3'-hydroxyl of the sugar moiety is in trans-relation to the base. Compounds which have not these structural features are resistant. Besides nucleosides which on enzymatic cleavage afford 5-fluorouracil, also the non-cleavable 1-(2-deoxy-β-L-ribofuranosyl)-5-fluorouracil (IX), 1-(2-deoxy-α-D-ribofuranosyl)-5-fluorouracil (XV) and 1-(2-deoxy-α-D-lyxofuranosyl)-5-fluorouracil (XIV) exhibit an antibacterial effect towards E. coli (ID50 1.0-2.5 . 10-5 M). This effect can be reversed by 2'-deoxyuridine but not by thymidine.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

scholarly journals A genetically detoxified derivative of heat-labile Escherichia coli enterotoxin induces neutralizing antibodies against the A subunit.

1994 ◽  
Vol 180 (6) ◽  
pp. 2147-2153 ◽  
Author(s):  
M Pizza ◽  
M R Fontana ◽  
M M Giuliani ◽  
M Domenighini ◽  
C Magagnoli ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cholera Toxin ◽  
Neutralizing Antibodies ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
E Coli ◽  
Heat Labile ◽  
A Subunit ◽  
Adp Ribosyltransferase ◽  
Derivatives Of

Escherichia coli enterotoxin (LT) and the homologous cholera toxin (CT) are A-B toxins that cause travelers' diarrhea and cholera, respectively. So far, experimental live and killed vaccines against these diseases have been developed using only the nontoxic B portion of these toxins. The enzymatically active A subunit has not been used because it is responsible for the toxicity and it is reported to induce a negligible titer of toxin neutralizing antibodies. We used site-directed mutagenesis to inactivate the ADP-ribosyltransferase activity of the A subunit and obtained nontoxic derivatives of LT that elicited a good titer of neutralizing antibodies recognizing the A subunit. These LT mutants and equivalent mutants of CT may be used to improve live and killed vaccines against cholera and enterotoxinogenic E. coli.

scholarly journals Enzymatic synthesis and phosphorolysis of 4(2)-thioxo- and 6(5)-azapyrimidine nucleosides by E. coli nucleoside phosphorylases

2016 ◽  
Vol 12 ◽  
pp. 2588-2601 ◽  
Author(s):  
Vladimir A Stepchenko ◽  
Anatoly I Miroshnikov ◽  
Frank Seela ◽  
Igor A Mikhailopulo
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Reaction Conditions ◽  
E Coli ◽  
No Formation ◽  
Structural Peculiarities ◽  
Substrate Properties ◽  
Nucleoside Phosphorylases ◽  
Derivatives Of

The trans-2-deoxyribosylation of 4-thiouracil (4SUra) and 2-thiouracil (2SUra), as well as 6-azauracil, 6-azathymine and 6-aza-2-thiothymine was studied using dG and E. coli purine nucleoside phosphorylase (PNP) for the in situ generation of 2-deoxy-α-D-ribofuranose-1-phosphate (dRib-1P) followed by its coupling with the bases catalyzed by either E. coli thymidine (TP) or uridine (UP) phosphorylases. 4SUra revealed satisfactory substrate activity for UP and, unexpectedly, complete inertness for TP; no formation of 2’-deoxy-2-thiouridine (2SUd) was observed under analogous reaction conditions in the presence of UP and TP. On the contrary, 2SU, 2SUd, 4STd and 2STd are good substrates for both UP and TP; moreover, 2SU, 4STd and 2’-deoxy-5-azacytidine (Decitabine) are substrates for PNP and the phosphorolysis of the latter is reversible. Condensation of 2SUra and 5-azacytosine with dRib-1P (Ba salt) catalyzed by the accordant UP and PNP in Tris∙HCl buffer gave 2SUd and 2’-deoxy-5-azacytidine in 27% and 15% yields, respectively. 6-Azauracil and 6-azathymine showed good substrate properties for both TP and UP, whereas only TP recognizes 2-thio-6-azathymine as a substrate. 5-Phenyl and 5-tert-butyl derivatives of 6-azauracil and its 2-thioxo derivative were tested as substrates for UP and TP, and only 5-phenyl- and 5-tert-butyl-6-azauracils displayed very low substrate activity. The role of structural peculiarities and electronic properties in the substrate recognition by E. coli nucleoside phosphorylases is discussed.

Coupling of Steroid O-(Carboxymethyl)oxime Derivatives with Amino Alcohols

1996 ◽  
Vol 61 (2) ◽  
pp. 288-297 ◽  
Author(s):  
Vladimír Pouzar ◽  
Ivan Černý
Keyword(s):  
Amino Acids ◽  
Hydroxy Group ◽  
Building Blocks ◽  
Amino Alcohols ◽  
New Approach ◽  
Alternative Synthesis ◽  
Oxime Derivatives ◽  
A Chain ◽  
Derivatives Of

New approach to the preparation of steroids with connecting bridge, based on an O-carboxymethyloxime (CMO) structure, and with terminal hydroxy group, is presented. 17-CMO derivatives of 3β-acetoxy- and 3β-methoxymethoxyandrost-5-en-17-one were condensed with α,ω-amino alcohols to give derivatives with a chain of seven to nine atoms. After THP-protection, these compounds were converted to 3-keto-4-ene derivatives. An alternative synthesis consisted in transformation of 17-CMO derivatives with bonded amino acids by reduction of the terminal carboxyl. The resulting compounds were designed as building blocks for the preparation of bis-haptens for sandwich immunoassays.

Preparation and Disulfide Interchange Reactions of Unsymmetrical Open-chain Derivatives of Cystine

1959 ◽  
Vol 81 (7) ◽  
pp. 1729-1734 ◽  
Author(s):  
Leonidas Zervas ◽  
Leo Benoiton ◽  
Ellinor Weiss ◽  
Milton Winitz ◽  
Jesse P. Greenstein
Keyword(s):  
Open Chain ◽  
Derivatives Of ◽  
Interchange Reactions

scholarly journals 4-Aminobutyrate (GABA) transporters from the amine-polyamine-choline superfamily: substrate specificity and ligand recognition profile of the 4-aminobutyrate permease from Bacillus subtilis

1998 ◽  
Vol 333 (3) ◽  
pp. 565-571 ◽  
Author(s):  
Casey E. BRECHTEL ◽  
Steven C. KING
Keyword(s):  
Bacillus Subtilis ◽  
Culture Conditions ◽  
Ligand Recognition ◽  
Open Chain ◽  
Conformationally Constrained ◽  
E Coli ◽  
Gaba Transporters ◽  
Transport Defect ◽  
Gaba Analogues ◽  
Limited Culture

A previous study [Ferson, Wray and Fisher (1996) Mol. Microbiol. 22, 693–701] has shown that transposon-mediated disruption of a protein 47% identical to the Escherichia coli GABA (4-aminobutyrate) transporter abolishes the ability of nitrogen-limited culture conditions to induce expression of a GABA transport activity in Bacillus subtilis. Here it is demonstrated directly that the B. subtilis GABA permease (gabP) gene can complement the transport defect in the gabP-negative E. colistrain. Unexpectedly, the ligand-recognition profile of the B. subtilis GabP was found to differ substantially from that of the highly homologous E. coli GabP. Unlike the E. coli GabP, the B. subtilis GabP: (i) exhibits approx. equal preference for the 3-carbon (β-alanine, Km = 9.6 µM) and the 4-carbon (GABA, Km = 37 µM) amino acids, and (ii) resists inhibition by bulky, conformationally constrained compounds (e.g. nipecotic acid, guvacine), which are active against GABA transporters from brain. The present study shows additionally that the B. subtilis GabP can translocate several open-chain GABA analogues (3-aminobutyrate, 3-aminopropanoate, cis-4-aminobutenoate) across the membrane via counterflow against [3H]GABA. Thus, consistent with the idea that the ligand-recognition domain of the B. subtilis GabP is less spacious than that of the close homologue from E. coli, the former exhibits more stringent requirements than the latter for substrate recognition and translocation. These distinct functional characteristics of the E. coli and B. subtilis GABA transporters provide a basis by which to identify ligand-recognition domains within the amine-polyamine-choline transporter superfamily.

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