The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Nguyen Thanh Thuong - One of the best experts on this subject based on the ideXlab platform.
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synthesis and binding properties of oligonucleotides covalently linked to an Acridine Derivative new study of the influence of the dye attachment site
Bioconjugate Chemistry, 1996Co-Authors: Ulysse Asseline, Edwige Bonfils, Daniel Dupret, Nguyen Thanh ThuongAbstract:2-Methoxy-6-chloro-9-aminoAcridine has been coupled via a polymethylene linker to various positions of an oligonucleotide chain: the 3‘-position, using a new universal support, the 5‘-position, and both 5‘- and 3‘-positions via a phosphate. The intercalating agent was also linked to the oligonucleotide chain via an internucleotide phosphorothiolate. The mixture of diastereoisomers was obtained as well as each pure Rp and Sp isomer. Finally, the Acridine moiety was introduced to the 5-position of the deoxyuridine. The binding properties of these oligonucleotide−Acridine conjugates with their DNA counterparts have been studied by absorption spectroscopy.
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synthesis and physicochemical properties of oligonucleotides built with either α l or β l nucleotides units and covalently linked to an Acridine Derivative
Nucleic Acids Research, 1991Co-Authors: Ulysse Asseline, Czernecki Stanislas, Thierry Le Diguarher, Marieclaude Perlat, Jeanmarc Valery, Nguyen Thanh ThuongAbstract:Modified deoxynucleosides 2'-deoxy-beta-L-uridine, beta-L-thymidine, alpha-L-thymidine, 2'-deoxy-beta-L-adenosine and 2'-deoxy-alpha-L-adenosine were synthesized and assembled as homooligomers, respectively: octa-beta-L-deoxyuridylates, octa beta-L and alpha-L-thymidylates and tetra beta-L and alpha-L-deoxyadenylates. These unnatural oligomers were then substituted with an Acridine Derivative. The binding studies of these modified oligonucleotides with D-ribo- and D-deoxyribopolynucleotides were carried out by absorption spectroscopy. While beta-L-d(Up)8m5Acr, beta-L-(Tp)8m5Acr, alpha-L-(Tp)8m5Acr did not interact with poly(rA) and poly(dA), beta-L-d(Ap)4m5Acr and alpha-L-d(Ap)4m5Acr did form double and triple helices with poly(rU) and poly(dT), respectively. Their stability towards nuclease digestion was studied through comparison with that of octa-beta-D-thymidylate and tetra beta-D-deoxyadenylate covalently linked to an Acridine Derivative. One endonuclease (nuclease P1 from Penicillium citrinum) and two exonucleases (a 3'-exonuclease from Crotalus durissus venom and a 5'-exonuclease extracted from calf thymus) were employed. beta-L- and alpha-L-oligomers demonstrate a high resistance toward nuclease digestion.
Ulysse Asseline - One of the best experts on this subject based on the ideXlab platform.
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synthesis and binding properties of oligonucleotides covalently linked to an Acridine Derivative new study of the influence of the dye attachment site
Bioconjugate Chemistry, 1996Co-Authors: Ulysse Asseline, Edwige Bonfils, Daniel Dupret, Nguyen Thanh ThuongAbstract:2-Methoxy-6-chloro-9-aminoAcridine has been coupled via a polymethylene linker to various positions of an oligonucleotide chain: the 3‘-position, using a new universal support, the 5‘-position, and both 5‘- and 3‘-positions via a phosphate. The intercalating agent was also linked to the oligonucleotide chain via an internucleotide phosphorothiolate. The mixture of diastereoisomers was obtained as well as each pure Rp and Sp isomer. Finally, the Acridine moiety was introduced to the 5-position of the deoxyuridine. The binding properties of these oligonucleotide−Acridine conjugates with their DNA counterparts have been studied by absorption spectroscopy.
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synthesis and physicochemical properties of oligonucleotides built with either α l or β l nucleotides units and covalently linked to an Acridine Derivative
Nucleic Acids Research, 1991Co-Authors: Ulysse Asseline, Czernecki Stanislas, Thierry Le Diguarher, Marieclaude Perlat, Jeanmarc Valery, Nguyen Thanh ThuongAbstract:Modified deoxynucleosides 2'-deoxy-beta-L-uridine, beta-L-thymidine, alpha-L-thymidine, 2'-deoxy-beta-L-adenosine and 2'-deoxy-alpha-L-adenosine were synthesized and assembled as homooligomers, respectively: octa-beta-L-deoxyuridylates, octa beta-L and alpha-L-thymidylates and tetra beta-L and alpha-L-deoxyadenylates. These unnatural oligomers were then substituted with an Acridine Derivative. The binding studies of these modified oligonucleotides with D-ribo- and D-deoxyribopolynucleotides were carried out by absorption spectroscopy. While beta-L-d(Up)8m5Acr, beta-L-(Tp)8m5Acr, alpha-L-(Tp)8m5Acr did not interact with poly(rA) and poly(dA), beta-L-d(Ap)4m5Acr and alpha-L-d(Ap)4m5Acr did form double and triple helices with poly(rU) and poly(dT), respectively. Their stability towards nuclease digestion was studied through comparison with that of octa-beta-D-thymidylate and tetra beta-D-deoxyadenylate covalently linked to an Acridine Derivative. One endonuclease (nuclease P1 from Penicillium citrinum) and two exonucleases (a 3'-exonuclease from Crotalus durissus venom and a 5'-exonuclease extracted from calf thymus) were employed. beta-L- and alpha-L-oligomers demonstrate a high resistance toward nuclease digestion.
Claude Helene - One of the best experts on this subject based on the ideXlab platform.
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triple helix formation with purine rich phosphorothioate containing oligonucleotides covalently linked to an Acridine Derivative
Nucleic Acids Research, 1997Co-Authors: Jerome Lacoste, Jeanchristophe Francois, Claude HeleneAbstract:Purine-rich (GA)- and (GT)-containing oligophosphorothioates were investigated for their triplex-forming potential on a 23 bp DNA duplex target. In our system, GA-containing oligophosphorothioates (23mer GA-PS) were capable of triplex formation with binding affinities lower than (GA)-containing oligophosphodiesters (23mer GA-PO). The orientation of the third strand 23mers GA-PS and GA-PO was antiparallel to the purine strand of the duplex DNA target. In contrast, (GT)-containing oligophosphorothioates (23mer GT-PS) did not support triplex formation in either orientation, whereas the 23mer GT-PO oligophosphodiester demonstrated triplex formation in the antiparallel orientation. GA-PS oligonucleotides, in contrast to GT-PS oligonucleotides, were capable of self-association, but these self-associated structures exhibited lower stabilities than those formed with GA-PO oligonucleotides, suggesting that homoduplex formation (previously described for the 23mer GA-PO sequence by Noonberg et al.) could not fully account for the decrease in triplex stability when phosphorothioate linkages were used. The 23mer GA-PS oligonucleotide was covalently linked via its 5'-end to an Acridine Derivative (23mer Acr-GA-PS). In the presence of potassium cations, this conjugate demonstrated triplex formation with higher binding affinity than the unmodified 23mer GA-PS oligonucleotide and even than the 23mer GA-PO oligonucleotide. A (GA)-containing oligophosphodiester with two phosphorothioate linkages at both the 5'- and 3'-ends exhibited similar binding affinity to duplex DNA compared with the unmodified GA-PO oligophosphodiester. This capped oligonucleotide was more resistant to nucleases than the GA-PO oligomer and thus represents a good alternative for ex vivo applications of (GA)-containing, triplex-forming oligonucleotides, allowing a higher binding affinity for its duplex target without rapid cellular degradation.
Takeo Shimidzu - One of the best experts on this subject based on the ideXlab platform.
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synthesis and properties of an oligonucleotide modified with an Acridine Derivative at the artificial abasic site
Bioconjugate Chemistry, 1996Co-Authors: K Fukui, Minoru Morimoto, Hiroshi Segawa, Kazuyoshi Tanaka, Takeo ShimidzuAbstract:The synthesis of an oligodeoxynucleotide (ODN) modified with 2-methoxy-6-chloro-9-aminoAcridine (Acr) at an abasic site is described. A stereochemically defined aminodiol, l-threoninol, was used to serve as artificial abasic nucleoside. The molecule was modified so as to be suitable for the standard phosphoramidite method and was incorporated into the interior of an ODN. In addition, N-hydroxysuccinimidyl N-[9-(6-chloro-2-methoxy)acridinyl]-6-aminocaproate has been synthesized for postsynthetic modification of the amino substrate of the l-threoninol moiety in the ODN. By using absorption spectroscopy, it is shown that oligo(dA) conjugated with Acridine binds with complementary strand in a 1:1 ratio. The melting temperature showed that the nonmodified (abasic) duplex is destabilized as a result of lacking in base at the abasic site, but the covalently linked Acridine ring compensates for the destabilization effect. The fluorescence quantum yield of the Acridine ring was enhanced by connection to oligo(dA) ...
Jerome Lacoste - One of the best experts on this subject based on the ideXlab platform.
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triple helix formation with purine rich phosphorothioate containing oligonucleotides covalently linked to an Acridine Derivative
Nucleic Acids Research, 1997Co-Authors: Jerome Lacoste, Jeanchristophe Francois, Claude HeleneAbstract:Purine-rich (GA)- and (GT)-containing oligophosphorothioates were investigated for their triplex-forming potential on a 23 bp DNA duplex target. In our system, GA-containing oligophosphorothioates (23mer GA-PS) were capable of triplex formation with binding affinities lower than (GA)-containing oligophosphodiesters (23mer GA-PO). The orientation of the third strand 23mers GA-PS and GA-PO was antiparallel to the purine strand of the duplex DNA target. In contrast, (GT)-containing oligophosphorothioates (23mer GT-PS) did not support triplex formation in either orientation, whereas the 23mer GT-PO oligophosphodiester demonstrated triplex formation in the antiparallel orientation. GA-PS oligonucleotides, in contrast to GT-PS oligonucleotides, were capable of self-association, but these self-associated structures exhibited lower stabilities than those formed with GA-PO oligonucleotides, suggesting that homoduplex formation (previously described for the 23mer GA-PO sequence by Noonberg et al.) could not fully account for the decrease in triplex stability when phosphorothioate linkages were used. The 23mer GA-PS oligonucleotide was covalently linked via its 5'-end to an Acridine Derivative (23mer Acr-GA-PS). In the presence of potassium cations, this conjugate demonstrated triplex formation with higher binding affinity than the unmodified 23mer GA-PS oligonucleotide and even than the 23mer GA-PO oligonucleotide. A (GA)-containing oligophosphodiester with two phosphorothioate linkages at both the 5'- and 3'-ends exhibited similar binding affinity to duplex DNA compared with the unmodified GA-PO oligophosphodiester. This capped oligonucleotide was more resistant to nucleases than the GA-PO oligomer and thus represents a good alternative for ex vivo applications of (GA)-containing, triplex-forming oligonucleotides, allowing a higher binding affinity for its duplex target without rapid cellular degradation.
