8-Methyladenosine-substituted analogues of 2-5A, p5'A2'p5'A2'p5'(me8A), p5'A2'p5'(me8A)2'p5'(me8A), p5'(me8A)2'p5'(me8A)2'p5'(me8A), and p5'(me8A) 2'p5'A2'p5'A, were prepared via a modification of a lead ion-catalyzed ligation reaction. These 2-5A monophosphates were converted into the corresponding 5'-triphosphates. Substitution of an 8-methyladenosine residue at the third position (2'-terminu...

1This study was supported by American Cancer Society Grant E587. 'Present address: University of Pennsylvania, School of Veterinary Medicine, New Bolton Center, Kennen Square, Pa. 19348. 3To whom reprint requests should be addressed. Present address: University of Colorado Medical Center, Department of Microbiology, Denver, Colo. 80220. 4The abbreviations used are: FdUrd, 5-fluoro-2-deoxyuridin...

Ecto-nucleoside triphosphate diphosphohydrolases (ecto-NTPDases), also known as ecto-ATPases and/or ectoapyrases, are integral membrane glycoproteins or soluble enzymes that are dependent on divalent cations. These ectoenzymes are important ecto-nucleotidases that are characterized by the ability to hydrolyze nucleoside triphosphates and nucleoside diphosphates to the monophosphate form. The hy...

Far-UV-induced formation of dimeric pyrimidine photoproducts within DNA is a major cause of the carcinogenic effects of solar light. The chemical structure of this class of lesion has been mostly determined by studies on model compounds. The present work is aimed at providing mass spectrometry data on the thymine-thymine photoproducts, including the diastereoisomers of the cyclobutane dimer, th...

Cyanobacteria are photosynthetic prokaryotic organisms that share characteristics with bacteria and chloroplasts regarding mRNA degradation. Synechocystis sp. PCC6803 is a model organism for cyanobacteria, but not much is known about the mechanism of RNA degradation. Only one member of the RNase II-family is present in the genome of Synechocystis sp PCC6803. This protein was shown to be essenti...

This 1H-NMR study provides experimental evidence for an intermolecular interaction between the dipeptide carnosine (beta-alanyl-L-histidine) and the purine nucleoside 5'-monophosphates 5'-AMP, 5'-GMP. From the observed upfield shifts of the purine nucleotide and imidazole proton resonances it is concluded that the interaction is of the stacking type and that it involves the purine base of the n...

Background The cyclic nucleotide monophosphates cGMP and cAMP play an essential role in many signaling pathways. The identification and profiling of cGMPand cAMP-binding proteins is an important step in order to elucidate the molecular basis of these pathways. In order to develop a tool to specifically target cGMPand cAMP-binding proteins, we synthesized cGMPand cAMP Capture CompoundsTM (CCs). ...

The 5'-nucleotide of small RNAs associates directly with the MID domain of Argonaute (AGO) proteins. In humans, the identity of the 5'-base is sensed by the MID domain nucleotide specificity loop and regulates the integrity of miRNAs. In Arabidopsis thaliana, the 5'-nucleotide also controls sorting of small RNAs into the appropriate member of the AGO family; however, the structural basis for th...

Polyinosinate (poly(I)] inhibited transfer RNA methylases prepared from the cell-soluble fraction and the nucleolar fraction of Novikoff rat hepatoma cells. Polyinosinate-cytidylate duplex, polyinosinate-cytidylate copolymer, and other homopolymers such as polycytidylate and polyadenylate showed very little effect. The mechanism of inhibition has been attributed to specific interactions between...

Prodrugs of therapeutic nucleoside monophosphates masked as phosphoramidate derivatives have become an increasingly important class of antiviral drugs in pharmaceutical research for delivering nucleotides in vitro and in vivo. Conventionally, phosphoramidate derivatives are prepared as a mixture of two diastereomers. We report a class of stable phosphoramidating reagents containing an amino aci...