Adenylate Trimer Research Articles

Probing the activation site of ribonuclease L with new N6-substituted 2′,5′-adenylate trimers

2-5A trimer [5′-monophosphoryladenylyl(2′-5′)adenylyl(2′-5′)adenosine] activates RNase L. While the 5′-terminal and 2′-terminal adenosine N 6-amino groups play a key role in binding to and activation of RNase L, the exocyclic amino function of the second adenylate (from the 5′-terminus) plays a relatively minor role in 2-5A's biological activity. To probe the available space proximal to the amino function of the central adenylate of 2-5A trimer during binding to RNase L, a variety of substituents were placed at that position. To accomplish this, the convertible building block 5′- O-dimethoxytrityl-3′- O-( tert-butyldimethylsilyl)-6-(2,4-dinitrophenyl)thioinosine 2′-(2-cyanoethyl N, N-diisopropylphosphoramidite) was prepared as a synthon to introduce 6-(2,4-dinitrophenyl)thioinosine into the middle position of the 2-5A trimer during automated synthesis. Post-synthetic treatment with aqueous amines transformed the (2,4-dinitrophenyl)thioinosine into N 6-substituted adenosines. Assays of these modified trimers for their ability to bind and activate RNase L showed that activation activity could be retained, albeit with some sacrifice compared to unmodified p5′A2′p5′A2′p5′A. Thus, the spatial domain about this N 6-amino function could be available for modifications to enhance the biological potency of 2-5A analogues and to ligate 2-5A to targeting vehicles such as antisense molecules.

ChemInform Abstract: Nucleotides. Part 59. Synthesis, Characterization, and Biological Activities of New Potential Antiviral Agents. (2′‐5′) Adenylate Trimer Analogues Containing 3′‐Deoxy‐3′‐(hexadecanoylamino)adenosine at the 2′‐Terminus.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleotides, Part LIX, Synthesis, Characterization, and Biological Activities of New Potential Antiviral Agents: (2′ - 5′)Adenylate Trimer Analogs Containing 3′-Deoxy-3′-(hexadecanoylamino)adenosine at the 2′-Terminus

Based upon 3′-amino-3′-deoxyadenosine (15), its protected 3′-hexadecanoylamino derivative 22 was chosen as starting material for the synthesis of a series of new modified 2′ – 5′-adenylate trimers 33 – 36 as potential antiviral agents. All (2′ – 5′)A trimer analogs 33 – 36 inhibit HIV-1 replication as measured by the inhibition of syncytia formation and inhibition of HIV-1 reverse transcriptase activity. Compound 34 inhibits HIV-1 reverse transcription by 100% and subsequently inhibits expression of HIV-1 p24. However, compound 35 acts differently, since it does not inhibit HIV-1 reverse transcription, HIV-1 integrase, or HIV-1 p24 expression. Therefore, 35 appears to exert its inhibitory effect at a later stage of HIV-1 replication, i.e., the budding process.

A 2′←5′-Adenylate Trimer With a Positively Charged 2′(3′)-Terminal 8-(4-Aminobunl)Aminoadenosine Residue: Synthesis, Conformation and RNase L Binding

An analogue of the 2-5A core trimer containing an 8-(4-aminobutyl)-aminoadenosine (1; A) residue at the 2′(3′)-terminus [2; (2′,5′)A2A*] was synthesized. The conformation of (2′,5′)A2A* was studied by 1H, 13C-NMR, and CD spectroscopy. The (2′,5′)A2A* exhibits very low binding ability to the RNase L of mouse L cells, but slightly enhanced resistance to digestion by SVPD compared to the parent trimer.

ChemInform Abstract: Nucleotides. Part 51. Synthesis and Biological Activities of (2′—5′)Adenylate Trimer Conjugates with 2′‐Terminal 3′‐O‐(ω‐Hydroxyalkyl) and 3′‐O‐(ω‐Carboxyalkyl) Spacers.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleotides Part LI. Synthesis and biological activities of (2′‐5′)adenylate trimer conjugates with 2′‐terminal 3′‐O(ω‐hydroxyalkyl) and 3′‐O‐(ω‐carboxyalkyl) spacers

AbstractAn efficient strategy for the synthesis of (2′‐5′)adenylate trimer conjugates with 2′‐terminal 3′‐O‐(ω‐hydroxyalkyl) and 3′‐O‐(ω‐carboxyalkyl) spacers is reported. Npeoc‐protected adenosine building blocks 37‐‐40 for phosphoramidite chemistry carrying a 3′‐O‐[11‐(levulinoyloxy)undecyl], 3′‐O‐{2‐[2‐(levulinoyloxy)ethoxy]ethyl}, 3′‐O‐[5‐(2‐cyanoethoxycarbonyl)pentyl], and 3′‐O‐{5‐[(9H‐fluoren‐9‐ylmethoxy)carbonyl]pentyl} moiety, respectively, were prepared (npeoc = 2‐(4‐nitrophenyl)ethoxycarbonyl). Condensation with the cordycepin (3′‐deoxyadenosine) dimer 1 led to the corresponding trimers 42, 43, 47, and 48. Whereas the levulinoyl (lev) and 9H‐fluoren‐9‐ylmethyl (fm) blocking groups could be cleaved off selectively from the trimers 42, 43, and 48 yielding the intermediates 44, 45, and 49 for the synthesis of the 3′‐O‐(ω‐hydroxyalkyl)trimers 53, 54 and the cholesterol conjugates 59‐‐61, the 2‐cyanoethyl (ce) protecting group of 47, however, could not be removed in a similar manner from the carboxy function. Trimer 47 served as precursor for the preparation of the trimer 55 with a terminal 3′‐O‐(5‐carboxypentyl)adenosine moiety. The metabolically stable 3′‐O‐alkyl‐(2′‐‐5′)A derivatives were tested regarding inhibition of HIV‐1 syncytia formation and HIV‐1 RT activity. Only the conjugate 59 showed significant effects, whereas the trimers 53‐‐55 and the conjugates 60 and 61 were less potent inhibitors, even at 100‐fold larger concentrations.

ChemInform Abstract: Nucleotides. Part 45. Synthesis of New (2′→5′)Adenylate Trimers, Containing 5′‐Amino‐5′‐deoxyadenosine Residues at the 5′‐End of the Oligoadenylate Chain, and of Its Analogues, Carrying a 9‐((2‐ Hydroxyethoxy)methyl)adenine Residue at the 2′‐Terminus.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleotides. Part XLV. Synthesis of new (2′–5′)adenylate trimers, containing 5′‐amino‐5′‐deoxyadenosine residues at the 5′‐end of the oligoadenylate chain, and of its analogues, carrying a 9‐[(2‐hydroxyethoxy)methyl]adenine residue at the 2′‐terminus

AbstractThe 5′‐amino‐5′‐deoxy‐2′,3′‐O‐isopropylideneadenosine (4) was obtained in pure form from 2′,3′‐O‐isopropylideneadenosine (1), without isolation of intermediates 2 and 3. The 2‐(4‐nitrophenyl)ethoxycarbonyl group was used for protection of the NH2 functions of 4 (→7). The selective introduction of the palmitoyl (= hexadecanoyl) group into the 5′‐N‐position of 4 was achieved by its treatment with palmitoyl chloride in MeCN in the presence of Et3N (→5). The 3′‐O‐silyl derivatives 11 and 14 were isolated by column chromatography after treatment of the 2′,3′‐O‐deprotected compounds 8 and 9, respectively, with (tert‐butyl)dimethylsilyl chloride and 1H‐imidazole in pyridine. The corresponding phosphoramidites 16 and 17 were synthesized from nucleosides 11 and 14, respectively, and (cyanoethoxy)bis(diisopropylamino)phosphane in CH2Cl2. The trimeric (2′–5′)‐linked adenylates 25 and 26 having the 5′‐amino‐5′‐deoxyadenosine and 5′‐deoxy‐5′‐(palmitoylamino)adenosine residue, respectively, at the 5′‐end were prepared by the phosphoramidite method. Similarly, the corresponding 5′‐amino derivatives 27 and 28 carrying the 9‐[(2‐hydroxyethoxy)methyl]adenine residue at the 2′‐terminus, were obtained. The newly synthesized compounds were characterized by physical means. The synthesized trimers 25–28 were 3‐, 15‐, 25‐, and 34‐fold, respectively, more stable towards phosphodiesterase from Crotalus durissus than the trimer (2′–5′)ApApA.

ChemInform Abstract: Nucleotides. Part 40. Synthesis and Characterization of Modified 2′‐5′ Adenylate Trimers ‐ Potential Antiviral Agents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleotides Part XL. Synthesis and Characterization of Modified 2′–5′ Adenylate Trimers–Potential Antiviral Agents

Abstract2′–5′ Adenylate trimers 41–44 carrying the (tert‐butyl)dimethylsilyl (tbds) group at the 3′‐OH position of various sugar moieties were synthesized via the phosphoramidite method. The use of the (tert‐butyloxy)carbonyl (boc) and 2‐(4‐nitrophenyl)ethylsulfonyl (npes) groups for 2′‐OH protection in neighbourhood to the 3′‐O‐tbds residue was compared during the synthesis of the target trimers. For other functional positions, the use of the 2‐(4‐nitrophenyl)ethyl (npe) and 2‐(4‐nitrophenyl)ethoxycarbonyl (npeoc) blocking groups were favoured.

The Relationship between Conformation and Biological Activity of 8-substituted Analogues of 2′,5′-Oligoadenylates

Analogues of the 2′,5′-linked adenylate trimer 5′-monophosphates, p5′A2′p5′A2′p5′A (pA3) (1a), containing 8-hydroxyadenosine and 8-mercaptoadenosine in the first, second, and third nucleotide positions were tested for their ability to bind to and activate RNase L of mouse L cells. The oligomer, p5′ASH2′p5′ASH2′p5′ASH(pASH3) (1c) had little capacity to bind to RNase L. On the other hand, an analogue of the p5′AOH2′p5′AOH2′p5′AOH(pAOH3) (1b) bound almost as well as the parent 2-5A [pppA(2′p5′A)2] (P3A3) (1d) to RNase L. The 8-substituted analogues of 2-5A were more resistant to degradation by (2′,5′) phosphodiesterase. Finally, the monophosphate, pASH3(1c) which possessed higher anti-HIV activity than pAg (1a) or pAOH3(1b).

Characterization and biological activity of 8-substituted analogues of 2′,5′-oligoadenylates

Analogues of the 2′,5′-linked adenylate trimer 5′-monophosphates (p5′A2′p5′A2′p5′A) containing 8-hydroxyadenosine and 8-mercaptoadenosine in the first, second, and third nucleotide positions were tested for their ability to bind to and activate RNase L of mouse L cells. Teh ability of p5′A SH2′p5′A SH2′p5′A SH (pA AH 3) (1c) to bind 2–5A dependent endonuclease was markedly decreased. On the other hand, an analogue of the 2′,5′-linked adenylate trimer monophosphate substituted by 8-hydroxyadenosine in the first, second, and third nucleotide positions bound almos as well as parent 2–5A [pppA(2′p5′A) 2] (p 3A 3) (1d) to RNase L. The 8-substituted analogues of 2–5A were more resistant to the degradation by the (2′,5′) phosphodiesterase. Of particular interest is monophosphate, pA SH 3 (1c) which possessed higher anti-HIV activity than pA 3 (1a) or pA OH 3 (1b).

ChemInform Abstract: Nucleotides. Part 38. Syntheses and Characterization of Phosphorothioate Analogues of (2′‐5′)Adenylate Dimer and Trimer and Their 5′‐O‐Monophosphates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nucleotides. Part XXXVI. Syntheses and biological characterization of phosphorothioate analogues of (3′–5′)adenylate trimer

AbstractThe four protected diastereoisomcrs 7a/7b and 8a/8b P‐thioadenylyl‐(3′–5′)‐P‐thioadenylyI‐(3′–5′)‐adenosine were synthesized, separated, and deblocked to the free oligonucleotides (Scheme). Biochemical characterization of these (3′–5′)phosphorothioate analogues of adenyiate trimer indicate that these compounds, and the corresponding 5′‐monophosphates, neither bind to nor activate RNase L, and are considered to be valuable control compounds in screening experiments.

Purine 8-substitution modulates the ribonuclease L binding and activation abilities of 2′, 5′-oligoadenylates

Analogues of the 2',5'-linked adenylate trimers monophosphate (p5'A2'p5'A2'p5'A) containing 8-hydroxypropyladenosine, 8-bromoadenosine, and 8-hydroxyadenosine in the first, second, and third nucleotide positions were tested for their ability to bind to and activate RNase L of mouse L cells. p5'AHPr2'p5'AHPr2'p5'AHPr (pAHPr3) (1b) and p5'ABr2'p5'ABr2'p5'ABr (pABr3) (1d) were markedly decreased in ability to bind to the 2-5A dependent endonuclease. On the other hand, analogue of the 2',5'-linked adenylate trimer monophosphate substituted by 8-hydroxyadenosine in the first, second, and third nucleotide position was bound about as well as parent 2-5A [pppA(2'p5'A)2] (p3A3) (1e) to RNase L. Additionally, p5'AOH2'p5'AOH2'p5'AOH (pAOH3) (1c) was as active as parent 2-5A in the rRNA cleavage assay, while pAHPr3 (1b) and pABr3 (1d) were devoid of activity. The 8-substituted analogues of 2-5A were more resistant to the degradation by the (2',5') phosphodiesterase. Finally of particular interest was monophosphate, pAOH3 (1c) which possessed nearly 100% of the translation inhibitory activity of 2-5A triphosphate itself. These results suggest that changes in the base-sugar torsion angles of 2-5A may modulate both binding to and activation of mouse L cell RNase L.

2- and 8-azido photoaffinity probes. 1. Enzymatic synthesis, characterization, and biological properties of 2- and 8-azido photoprobes of 2-5A and photolabeling of 2-5A binding proteins.

The 2- and 8-azido trimer 5'-triphosphate photoprobes of 2-5A have been enzymatically synthesized from [gamma-32P]2-azidoATP and [alpha-32P]8-azidoATP by 2-5A synthetase from rabbit reticulocyte lysates. Identification and structural determination of the 2- and 8-azido adenylate trimer 5'-triphosphates were accomplished by enzymatic hydrolyses with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase. Hydrolysis products were identified by HPLC and PEI-cellulose TLC analyses. The 8-azido photoprobe of 2-5A displaces p3A4[32P]pCp from RNase L with affinity equivalent to p3A3 (IC50 = 2 X 10(-9) M in radiobinding assays). The 8-azido photoprobe also activates RNase L to hydrolyze poly(U) [32P]pCp 50% at 7 X 10(-9) M in core-cellulose assays. The 2- and 8-azido photoprobes and authentic p3A3 activate RNase L to cleave 28S and 18S rRNA to specific cleavage products at 10(-9) M in rRNA cleavage assays. The nucleotide binding site(s) of RNase L and/or other 2-5A binding proteins in extracts of interferon-treated L929 cells were investigated by photoaffinity labeling. Dramatically different photolabeling patterns were observed with the 2- and 8-azido photoprobes. The [gamma-32P]2-azido adenylate trimer 5'-triphosphate photolabels only one polypeptide with a molecular weight of 185,000 as determined by SDS gel electrophoresis, whereas the [alpha-32P]8-azido adenylate trimer 5'-triphosphate covalently photolabels six polypeptides with molecular weights of 46,000, 63,000, 80,000, 89,000, 109,000, and 158,000. Evidence that the photolabeling by 2- and 8-azido 2-5A photoprobes was highly specific for the p3A3 allosteric binding site was obtained as follows.(ABSTRACT TRUNCATED AT 250 WORDS)

Purine 8-bromination modulates the ribonuclease L binding and activation abilities of 2',5'-oligoadenylates. Possible influence of glycosyl torsion angle.

Analogs of the 2',5'-linked adenylate trimer diphosphate (pp5'A2'p5'A2'p5'A or 2-5A) containing 8-bromoadenosine in the first, second, third, first and third, or second and third nucleotide positions (from the 5' terminus) were synthesized and found to vary dramatically in their ability to bind to and activate the RNase L of mouse L cells. Whenever the 8-bromoadenosine residue was substituted for adenosine in the first or 5'-terminal residue, there resulted a marked decrease in ability to bind to the 2-5A-dependent endonuclease. A similar result was obtained when the second adenosine nucleotide was replaced by 8-bromoadenosine. To the contrary, all analogs that bore an 8-bromoadenosine (br8A) in the third or 2'-terminal position were bound about as well as parent 2-5A to RNase L. Additionally, the 5'-diphosphate pp5'A2'p5'A2'p5' (br8A) was 10 times more effective than 2-5A as an inhibitor of translation. An increase in stability could not explain this significantly enhanced ability since the 2'-terminally brominated analog showed a similar half-life to 2-5A itself. Finally of particular interest was the analog monophosphate p5'A2'p5'(br8A)2'p5'(br8A) which possessed nearly 10% of the translational inhibitory activity of 2-5A triphosphate itself. These results suggest that changes in the base-sugar torsion angles of 2-5A may modulate both binding to and activation of mouse L cell RNase L.

Synthesis of 2′-5′ Adenylate Trimers Containing 3′-Modified β-D-Xylofuranosyl-Adenine Derivatives at the 2′-End

Abstract The exciting reports (1,2) on the unusual structure of the oligonucleotide pppAZ1p5′A2′p5′A and its biological activity as a strong inhibitor of cell free protein synthesis (3) motivated various research groups to synthesize this low-molecular-weight 01 igonucleotide and its analogues (4,5). Since the biological activity of the 2′-5′-adenylates is rapidly lost due to cleavage of the 2′-5′-internucleotidic bond by a specific phosphodiesterase working from the 2′-end and affording a 3′-hydroxyl ribo-moiety modifications at this part of the molecule may enhance the stability towards enzymatic degradation and prolong this way the biological activity.

ChemInform Abstract: Synthesis and Properties of 2′,5′‐Adenylate Trimers Bearing 2′‐Terminal 8‐Bromo‐ or 8‐Hydroxyadenosine.

Chemischer InformationsdienstVolume 17, Issue 46 Natural Products ChemInform Abstract: Synthesis and Properties of 2′,5′-Adenylate Trimers Bearing 2′-Terminal 8-Bromo- or 8-Hydroxyadenosine. S. YOSHIDA, S. YOSHIDASearch for more papers by this authorH. TAKAKU, H. TAKAKUSearch for more papers by this author S. YOSHIDA, S. YOSHIDASearch for more papers by this authorH. TAKAKU, H. TAKAKUSearch for more papers by this author First published: November 18, 1986 https://doi.org/10.1002/chin.198646344AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume17, Issue46November 18, 1986 RelatedInformation

Synthesis and properties of 2',5'-adenylate trimers bearing 2'-terminal 8-bromo- or 8-hydroxyadenosine.

Trimers of 2', 5'-oligoadenylic acids bearing 2'-terminal 8-bromo- or 8-hydroxyadenosine have been synthesized by the phosphotriester method. Some properties of these compounds were studied by circular dichroism (CD) spectroscopy. The 2', 5'-adenylate trimer, A2'p5'A2'p5'HOA (10a) was found to have a less stacked structure than the 2', 5'-adenylate trimers A2'p5'A2'p5'BrA (11) and A2'p5'A2'p5'A (10b).