Search results

1

Structure and tautomerism of the neutral and monoanionic forms of 2-thiouracil, 2,4-dithiouracil, their nucleosides, and some related derivatives

100%

Psoda A., Shugar D.

Acta Biochimica Polonica

|

1979

|

vol. 26

|

issue 1-2

55-72

2

Halogenated benzimidazole inhibitors of phosphorylation, in vitro and in vivo, of the surface acidic proteins of the yeast ribosomal 60S subunit by endogenous protein kinases CK-II and PK60S

81%

Szyszka R., Boguszewska A., Shugar D., Grankowski N.

Acta Biochimica Polonica

|

1996

|

vol. 43

|

issue 2

389-396

3

Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways.

81%

Kulikowska E., Kierdaszuk B., Shugar D.

|

vol. 51

|

issue 2

493-531

EN

The 6-oxopurine xanthine (Xan, neutral form 2,6-diketopurine) differs from the corresponding 6-oxopurines guanine (Gua) and hypoxanthine (Hyp) in that, at physiological pH, it consists of a ≈ 1:1 equilibrium mixture of the neutral and monoanionic forms, the latter due to ionization of N(3)-H, in striking contrast to dissociation of the N(1)-H in both Gua and Hyp at higher pH. In xanthosine (Xao) and its nucleotides the xanthine ring is predominantly, or exclusively, a similar monoanion at physiological pH. The foregoing has, somewhat surprisingly, been widely overlooked in studies on the properties of these compounds in various enzyme systems and metabolic pathways, including, amongst others, xanthine oxidase, purine phosphoribosyltransferases, IMP dehydrogenases, purine nucleoside phosphorylases, nucleoside hydrolases, the enzymes involved in the biosynthesis of caffeine, the development of xanthine nucleotide-directed G proteins, the pharmacological properties of alkylxanthines. We here review the acid/base properties of xanthine, its nucleosides and nucleotides, their N-alkyl derivatives and other analogues, and their relevance to studies on the foregoing. Included also is a survey of the pH-dependent helical forms of polyxanthylic acid, poly(X), its ability to form helical complexes with a broad range of other synthetic homopolynucleotides, the base pairing properties of xanthine in synthetic oligonucleotides, and in damaged DNA, as well as enzymes involved in circumventing the existence of xanthine in natural DNA.

4

Acyclonucleosides: Acyclobenzimidazole nucleoside and nucleotide analogues and conformations of the acyclic chains by means of NMR spectroscopy

81%

Kazimierczuk Z., Stolarski R., Shugar D.

Acta Biochimica Polonica

|

1984

|

vol. 31

|

issue 1

33-48

5

Mechanism of hydroxylamine mutagenesis: An infrared study of the association in non-polar solutions of 5-methyl-Ni^4-hydroxycytosines

81%

Kulińska K., Psoda A., Shugar D.

Acta Biochimica Polonica

|

1980

|

vol. 27

|

issue 1

57-65

6

5-substituted arabinofuranosyluracil nucleosides: synthesis and antiviral properties

81%

Kulikowski T., Clercq Z. Z. E. d., Shugar D.

Acta Biochimica Polonica

|

1984

|

vol. 31

|

issue 3

341-356

7

Cyclic phosphates of some antiviral acyclonucleosides: relationship between conformation and substrate/inhibitor properties in some enzyme systems

81%

Cieśla J. M., Stolarski R., Shugar D.

|

vol. 40

|

issue 2

251-260

8

Hydroxylamine and methoxyamine mutagenesis: Tautomeric equilibrium of the promutagenic analogue, N^6-methoxyadenosine, in solvents of different polarities

81%

Kierdaszuk B., Stolarski R., Shugar D.

Acta Biochimica Polonica

|

1984

|

vol. 31

|

issue 1

49-64

9

Preparation of O'-methyl derivatives of 9-β-D-xylofuranosyladenine

81%

Darżynkiewicz E., Rudzińska I. E. L. D. A., Shugar D.

Acta Biochimica Polonica

|

1977

|

vol. 24

|

issue 3

215-224

10

Electrochemical reduction products of azido nucleosides, including Zidovudine (AZT): mechanisms and relevance to their intracellular metabolism

81%

Kawczyński W., Czochralska B., Shugar D.

|

vol. 40

|

issue 2

213-223

11

Mutagenesis induced by 5-bromouracil and methyl methane sulfonate: Role of DNA polymerase I

81%

Pietrzykowska I., Krych M., Shugar D.

Acta Biochimica Polonica

|

1984

|

vol. 31

|

issue 1

65-75

12

Preparation and properties of formycin analogues methylated on the pyrazolo ring nitrogens and/or the ribose cis-hydroxyls

80%

Giziewicz J., Shugar D.

Acta Biochimica Polonica

|

1977

|

vol. 24

|

issue 3

231-246

13

Halogen bonds involved in binding of halogenated ligands by protein kinases

72%

Poznański J., Winiewska M., Czapinska H., Poznańska A., Shugar D.

|

2016

|

vol. 63

|

issue 2

203-214

EN

Analysis of 664 known structures of protein kinase complexes with halogenated ligands revealed 424 short contacts between a halogen atom and a potential protein X-bond acceptor, the topology and geometry of which were analyzed according to the type of a halogen atom (X = Cl, Br, I) and a putative protein X-bond acceptor. Among 236 identified halogen bonds, the most represented ones are directed to backbone carbonyls of the hinge region and may replace the pattern of ATP-like hydrogen bonds. Some halogen-π interactions with either aromatic residues or peptide bonds, that accompany the interaction with the hinge region, may possibly enhance ligand selectivity. Interestingly, many of these halogen-π interactions are bifurcated. Geometrical preferences identify iodine as the strongest X-bond donor, less so bromine, while virtually no such preferences were observed for chlorine; and a backbone carbonyl as the strongest X-bond acceptor. The presence of a halogen atom in a ligand additionally affects the properties of proximal hydrogen bonds, which according to geometrical parameters get strengthened, when a nitrogen of a halogenated ligand acts as the hydrogen bond donor.

14

Analogues of formiycins A and B: Synthesis and some properties of methyl derivatives of 7-amino and 7-keto pyrazolo(4,3-d)pyrimidines

72%

Wierzchowski J., Kuśmierek J., Giziewicz J., Salvi D., Shugar D.

Acta Biochimica Polonica

|

1980

|

vol. 27

|

issue 1

35-56

15

Unusual nucleoside triphosphate donors for nucleoside kinases: 3'-Deoxyadenosine-2'-triphosphate and 2'-deoxyadenosine-3'-triphosphate

72%

Krawiec K., Kierdaszuk B., Kalinichenko E. N., Mikhailopulo I. A., Shugar D.

Acta Biochimica Polonica

|

1998

|

vol. 45

|

issue 1

87-94

16

Kinetics of deamination of cytosine nucleosides with etherified sugar hydroxyls

71%

Dudycz L., Darżynkiewicz E., Shugar D.

Acta Biochimica Polonica

|

1977

|

vol. 24

|

issue 3

207-214

17

Solution conformations of the antimetabolite 9-β-D-xylofuranosyladenine and its 8-bromo analogue

70%

Ekiel I., Shugar D.

Acta Biochimica Polonica

|

1979

|

vol. 26

|

issue 4

435-444

18

Acyclic analogues of 5-fluoro-dUMP and 5-fluoro-2'-deoxyuridine: Synthesis and inhibition of thymidylate synthase and tumour cell growth

62%

Felczak K., Gołos B., Dzik J. M., Rode W., Bretner M., Shugar D., Kulikowski T.

Acta Biochimica Polonica

|

1998

|

vol. 45

|

issue 1

75-82

19

Methylation and tautomerism of 1-substituted 5-fluorocytosines

60%

Kulikowski T., Shugar D.

Acta Biochimica Polonica

|

1979

|

vol. 26

|

issue 1-2

145-160

20

The NTP phosphate donor in kinase reactions: Is ATP a monopolist?

60%

Shugar D.

Acta Biochimica Polonica

|

1996

|

vol. 43

|

issue 1

9-23

Refine search results

Structure and tautomerism of the neutral and monoanionic forms of 2-thiouracil, 2,4-dithiouracil, their nucleosides, and some related derivatives

Halogenated benzimidazole inhibitors of phosphorylation, in vitro and in vivo, of the surface acidic proteins of the yeast ribosomal 60S subunit by endogenous protein kinases CK-II and PK60S

Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways.

Acyclonucleosides: Acyclobenzimidazole nucleoside and nucleotide analogues and conformations of the acyclic chains by means of NMR spectroscopy

Mechanism of hydroxylamine mutagenesis: An infrared study of the association in non-polar solutions of 5-methyl-Ni^4-hydroxycytosines

5-substituted arabinofuranosyluracil nucleosides: synthesis and antiviral properties

Cyclic phosphates of some antiviral acyclonucleosides: relationship between conformation and substrate/inhibitor properties in some enzyme systems

Hydroxylamine and methoxyamine mutagenesis: Tautomeric equilibrium of the promutagenic analogue, N^6-methoxyadenosine, in solvents of different polarities

Preparation of O'-methyl derivatives of 9-β-D-xylofuranosyladenine

Electrochemical reduction products of azido nucleosides, including Zidovudine (AZT): mechanisms and relevance to their intracellular metabolism

Mutagenesis induced by 5-bromouracil and methyl methane sulfonate: Role of DNA polymerase I

Preparation and properties of formycin analogues methylated on the pyrazolo ring nitrogens and/or the ribose cis-hydroxyls

Halogen bonds involved in binding of halogenated ligands by protein kinases

Analogues of formiycins A and B: Synthesis and some properties of methyl derivatives of 7-amino and 7-keto pyrazolo(4,3-d)pyrimidines

Unusual nucleoside triphosphate donors for nucleoside kinases: 3'-Deoxyadenosine-2'-triphosphate and 2'-deoxyadenosine-3'-triphosphate

Kinetics of deamination of cytosine nucleosides with etherified sugar hydroxyls

Solution conformations of the antimetabolite 9-β-D-xylofuranosyladenine and its 8-bromo analogue

Acyclic analogues of 5-fluoro-dUMP and 5-fluoro-2'-deoxyuridine: Synthesis and inhibition of thymidylate synthase and tumour cell growth

Methylation and tautomerism of 1-substituted 5-fluorocytosines

The NTP phosphate donor in kinase reactions: Is ATP a monopolist?