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C Richardson - One of the best experts on this subject based on the ideXlab platform.
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zinc binding domain of the bacteriophage t7 dna primase modulates binding to the dna template
Journal of Biological Chemistry, 2012Co-Authors: Barak Akabayov, C RichardsonAbstract:The zinc-binding domain (ZBD) of prokaryotic DNA primases has been postulated to be crucial for recognition of specific sequences in the single-stranded DNA template. To determine the molecular basis for this role in recognition, we carried out homolog-scanning mutagenesis of the zinc-binding domain of DNA primase of bacteriophage T7 using a bacterial homolog from Geobacillus stearothermophilus. The ability of T7 DNA primase to catalyze template-directed oligoribonucleotide synthesis is eliminated by substitution of any five-amino acid residue-long segment within the ZBD. The most significant defect occurs upon substitution of a region (Pro-16 to Cys-20) spanning two cysteines that coordinate the zinc ion. The role of this region in primase function was further investigated by generating a protein library composed of multiple amino acid substitutions for Pro-16, Asp-18, and Asn-19 followed by genetic screening for functional proteins. Examination of proteins selected from the screening reveals no change in sequence-specific recognition. However, the more positively charged residues in the region facilitate DNA binding, leading to more efficient oligoribonucleotide synthesis on short templates. The results suggest that the zinc-binding mode alone is not responsible for sequence recognition, but rather its interaction with the RNA polymerase domain is critical for DNA binding and for sequence recognition. Consequently, any alteration in the ZBD that disturbs its conformation leads to loss of DNA-dependent oligoribonucleotide synthesis.
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acidic residues in the nucleotide binding site of the bacteriophage t7 dna primase
Journal of Biological Chemistry, 2005Co-Authors: C RichardsonAbstract:Abstract DNA primases catalyze the synthesis of Oligoribonucleotides to initiate lagging strand DNA synthesis during DNA replication. Like other prokaryotic homologs, the primase domain of the gene 4 helicase-primase of bacteriophage T7 contains a zinc motif and a catalytic core. Upon recognition of the sequence, 5′-GTC-3′ by the zinc motif, the catalytic site condenses the cognate nucleotides to produce a primer. The TOPRIM domain in the catalytic site contains several charged residues presumably involved in catalysis. Each of eight acidic residues in this region was replaced with alanine, and the properties of the altered primases were examined. Six of the eight residues (Glu-157, Glu-159, Asp-161, Asp-207, Asp-209, and Asp-237) are essential in that altered gene 4 proteins containing these mutations cannot complement T7 phage lacking gene 4 for T7 growth. These six altered gene 4 proteins can neither synthesize primers de novo nor extend an oligoribonucleotide. Despite the inability to catalyze phosphodiester bond formation, the altered proteins recognize the sequence 5′-GTC-3′ in the template and deliver preformed primer to T7 DNA polymerase. The alterations in the TOPRIM domain result in the loss of binding affinity for ATP as measured by surface plasmon resonance assay together with ATP-agarose affinity chromatography.
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essential lysine residues in the rna polymerase domain of the gene 4 primase helicase of bacteriophage t7
Journal of Biological Chemistry, 2001Co-Authors: C RichardsonAbstract:Abstract At a replication fork DNA primase synthesizes Oligoribonucleotides that serve as primers for the lagging strand DNA polymerase. In the bacteriophage T7 replication system, DNA primase is encoded by gene 4 of the phage. The 63-kDa gene 4 protein is composed of two major domains, a helicase domain and a primase domain located in the C- and N-terminal halves of the protein, respectively. T7 DNA primase recognizes the sequence 5′-NNGTC-3′ via a zinc motif and catalyzes the template-directed synthesis of tetraribonucleotides pppACNN. T7 DNA primase, like other primases, shares limited homology with DNA-dependent RNA polymerases. To identify the catalytic core of the T7 DNA primase, single-point mutations were introduced into a basic region that shares sequence homology with RNA polymerases. The genetically altered gene 4 proteins were examined for their ability to support phage growth, to synthesize functional primers, and to recognize primase recognition sites. Two lysine residues, Lys-122 and Lys-128, are essential for phage growth. The two residues play a key role in the synthesis of phosphodiester bonds but are not involved in other activities mediated by the protein. The altered primases are unable to either synthesize or extend an oligoribonucleotide. However, the altered primases do recognize the primase recognition sequence, anneal an exogenous primer 5′-ACCC-3′ at the site, and transfer the primer to T7 DNA polymerase. Other lysines in the vicinity are not essential for the synthesis of primers.
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characterization of a novel dna primase from the salmonella typhimurium bacteriophage sp6
Biochemistry, 2000Co-Authors: Timothy Y Tseng, David N Frick, C RichardsonAbstract:The gene for the DNA primase encoded by Salmonella typhimurium bacteriophage SP6 has been cloned and expressed in Escherichia coli and its 74-kDa protein product purified to homogeneity. The SP6 primase is a DNA-dependent RNA polymerase that synthesizes short Oligoribonucleotides containing each of the four canonical ribonucleotides. GTP and CTP are both required for the initiation of oligoribonucleotide synthesis. In reactions containing only GTP and CTP, SP6 primase incorporates GTP at the 5‘-end of Oligoribonucleotides and CMP at the second position. On synthetic DNA templates, pppGpC dinucleotides are synthesized most rapidly in the presence of the sequence 5‘-GCA-3‘. This trinucleotide sequence, containing a cryptic dA at the 3‘-end, differs from other known bacterial and phage primase recognition sites. SP6 primase shares some properties with the well-characterized E. coli bacteriophage T7 primase. The T7 DNA polymerase can use Oligoribonucleotides synthesized by SP6 primase as primers for DNA synth...
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interaction of bacteriophage t7 gene 4 primase with its template recognition site
Journal of Biological Chemistry, 1999Co-Authors: David N Frick, C RichardsonAbstract:Abstract The primase fragment of the bacteriophage T7 63-kDa gene 4 helicase/primase protein contains the 271 N-terminal amino acid residues and lacks helicase activity. The primase fragment catalyzes the synthesis of Oligoribonucleotides at rates similar to those catalyzed by the full-length protein in the presence of a 5-nucleotide DNA template containing a primase recognition site (5′-GGGTC-3′, 5′-TGGTC-3′, 5′-GTGTC-3′, or 5′-TTGTC-3′). Although it is not copied into the Oligoribonucleotides, the cytosine at the 3′-position is essential for synthesis and template binding. Two nucleotides flanking the 3′-end of the recognition site are required for tight DNA binding and rapid oligoribonucleotide synthesis. Nucleotides added to the 5′-end have no effect on the rate of oligoribonucleotide synthesis or the affinity of the primase for DNA. The binding of either ATP or CTP significantly increases the affinity of the primase for its DNA template. DNA lacking a primase recognition site does not inhibit oligoribonucleotide synthesis, suggesting that the primase binds DNA in a sequence-specific manner. The affinity of the primase for templates is weak, ranging from 10 to 150 μm. The tight DNA binding (<1 μm) observed with the 63-kDa gene 4 protein occurs viainteractions between DNA templates and the helicase domain.
Ira G Wool - One of the best experts on this subject based on the ideXlab platform.
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a determination of the identity elements in yeast 18 s ribosomal rna for the recognition of ribosomal protein ys11 the role of the kink turn motif in helix 11
Journal of Molecular Biology, 2005Co-Authors: John Dresios, Yuenling Chan, Ira G WoolAbstract:A description of the site of interaction of YS11, the yeast homolog of eubacterial S17, with 18 S rRNA was obtained by assessing the binding of the ribosomal protein, in a filter retention assay, to Oligoribonucleotides that reproduce regions of 18 S rRNA. YS11 binds predominantly to domain I; the Kd value is 113 nM. The dimensions of the YS11 binding site were refined, guided by chemical protection data and by the atomic structure of the Thermus thermophilus 30 S subunit, which has the S17 recognition site in 16 S rRNA. An oligoribonucleotide that mimics helix 11, a phylogenetically conserved region in domain I, binds YS11 with a Kd value of 230 nM; a second oligoribonucleotide that contains only the kink-turn motif in helix 11 binds YS11 with a Kd value of 528 nM. Thus, helix 11 has most of the nucleotides required for the recognition of YS11. To identify those nucleotides a set of 27 transversion mutations in H11 was constructed and their contribution to the binding of YS11 determined. Mutations of nine nucleotides (U313, C314, A316, G337, C338, G347, U348, U350, and C351) increased the Kd value for YS11 binding by at least eightfold; G325U and U349A mutations increased the Kd value fivefold. Eight of the 11 mutations are in the kink–turn in H11, confirming the critical importance of the motif for YS11 recognition. The other three nucleotides are in the lower stem and the terminal loop of H11, which makes a lesser, but still important, contribution to YS11 binding. The identity elements for YS11 recognition are: A316, G325, G337, G347, U348, U349, U350, and C351. The effect of the other nucleotides that decrease binding is probably indirect, presumably they affect the conformation of the binding site but do not have contacts to YS11 amino acid residues. The eight identity element nucleotides are in regions of H11 that deviate from A-form geometry and the contacts are predominantly, if not exclusively, to backbone phosphate and sugar oxygen atoms, indicating that YS11 recognizes the shape of the rRNA binding site rather than reading the sequence of nucleotides.
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the ribosome in pieces binding of elongation factor ef g to Oligoribonucleotides that mimic the sarcin ricin and thiostrepton domains of 23s ribosomal rna
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Alexander Munishkin, Ira G WoolAbstract:An oligoribonucleotide (a 27-mer) that mimics the sarcin/ricin (S/R) domain of Escherichia coli 23S rRNA binds elongation factor EF-G; the Kd is 6.9 μM, whereas for binding to ribosomes it is 0.7 μM. Binding saturates when EF-G and the S/R RNA are equimolar; at saturation 70% of the input RNA is in complexes with EF-G. Binding of EF-G to S/R RNA does not require GTP but is inhibited by GDP; the inhibition by GDP is overcome by GTP. The effects of mutations of the S/R domain nucleotides G2655, A2660, and G2661 suggest that EF-G recognizes the conformation of the RNA rather than the identity of the nucleotides. EF-G also binds to an oligoribonucleotide (an 84-mer) that has the thiostrepton region of 23S rRNA; however, EF-G binds independently to S/R and thiostrepton Oligoribonucleotides.
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dependence of depurination of Oligoribonucleotides by ricin a chain on divalent cations and chelating agents
Iubmb Life, 1996Co-Authors: Anton Gluck, Ira G WoolAbstract:: Ricin A-chain is a cytotoxic RNA N-glycosidase that inactivates eukaryotic ribosomes by depurinating the adenosine at position 4324 in 28S rRNA. The enzyme retains its specificity when a synthetic oligoribonucleotide (a 35-mer) that mimics the structure at the site of action is the substrate. However, covalent modification by ricin A-chain of the oligoribonucleotide but not of ribosomes, depends on the simultaneous presence of a divalent cation and a chelating agent.
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determination of the 28 s ribosomal rna identity element g4319 for alpha sarcin and the relationship of recognition to the selection of the catalytic site
Journal of Molecular Biology, 1996Co-Authors: Anton Gluck, Ira G WoolAbstract:Ricin A-chin and alpha-sarcin are ribotoxins that inactivate eukaryotic ribosomes by modifying 28 S rRNA; ricin A-chain is an RNA N-glycosidase that depurinates the adenosine at position 4324 and alpha-sarcin is a ribonuclease that cleaves the phosphodiester bond on the 3' side of the adjacent guanosine (at position 4325). In cartoons of the secondary structure these two residues are seen to be embedded in a 17 base single-stranded loop over a seven base-pair helix. However, NMR spectroscopy of an oligoribonucleotide, a 29-mer that mimics the sarcin/ricin domain, indicates that the RNA has a compact conformation in which the guanosine at the position analogous to 4319 in 28 S rRNA is bulged out of what otherwise is an extended A-form helix. Since similar structural irregularities are used by proteins to bind to RNA, we have tested the effect of mutations of the bulged guanosine on recognition and covalent modification of the RNA by ricin A-chain and by alpha-sacrin. For the test a synthetic oligoribonucletide, a 35-mer, was used; the mutations were the deletion, the transition to adenosine, and the transversion to cytidine and uridine of the guanosine that is the analog of G4319. Each of the four mutations abolished cleavage og the RNA by alpha-sacrin, where depurination by ricin A-chain was little affected. Thus G4319 is an identity element for alpha-sacrin recognition. Analysis of the effect of alpha-sacrin on variant Oligoribonucleotides in which additional bases were inserted between the identity element guanosine and the site of catalysis suggest that on binding to the RNA the toxin uses the guanosine for orientation and then cleaves at a fixed distance and at a fixed position in space.
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ribosomal rna identity elements for ricin a chain recognition and catalysis analysis with tetraloop mutants
Journal of Molecular Biology, 1992Co-Authors: Anton Gluck, Yaeta Endo, Ira G WoolAbstract:Ricin is a cytotoxic protein that inactivates ribosomes by hydrolyzing the N-glycosidic bond between the base and the ribose of the adenosine at position 4324 in eukaryotic 28 S rRNA. Ricin A-chain will also catalyze depurination in naked prokaryotic 16 S rRNA; the adenosine is at position 1014 in a GAGA tetraloop. The rRNA identity elements for recognition by ricin A-chain and for the catalysis of cleavage were examined using synthetic GAGA tetraloop Oligoribonucleotides. The RNA designated wild-type, an oligoribonucleotide (19-mer) that approximates the structure of the ricin-sensitive site in 16 S rRNA, and a number of mutants were transcribed in vitro from synthetic DNA templates with phage T7 RNA polymerase. With the wild-type tetraloop oligoribonucleotide the ricin A-chain-catalyzed reaction has a Km of 5.7 microM and a Kcat of 0.01 min-1. The toxin alpha-sarcin, which cleaves the phosphodiester bond on the 3' side of G4325 in 28 S rRNA, does not recognize the tetraloop RNA, although alpha-sarcin does affect a larger synthetic oligoribonucleotide that has a 17-nucleotide loop with a GAGA sequence; thus, there is a clear divergence in the identity elements for the two toxins. Mutants were constructed with all of the possible transitions and transversions of each nucleotide in the GAGA tetraloop; none was recognized by ricin A-chain. Thus, there is an absolute requirement for the integrity of the GAGA sequence in the tetraloop. The helical stem of the tetraloop oligoribonucleotide can be reduced to three base-pairs, indeed, to two base-pairs if the temperature is decreased, without affecting recognition; the nature of these base-pairs does not influence recognition or catalysis by ricin A-chain. If the tetraloop is opened so as to form a GAGA-containing hexaloop, recognition by ricin A-chain is lost. This suggests that during the elongation cycle, a GAGA tetraloop either exists or is formed in the putative 17-member single-stranded region of the ricin domain in 28 S rRNA and this bears on the mechanism of protein synthesis.
Wang-yi Liu - One of the best experts on this subject based on the ideXlab platform.
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In vitro interaction of eukaryotic elongation factor 2 with synthetic oligoribonucleotide that mimics GTPase domain of rat 28S ribosomal RNA.
The International Journal of Biochemistry & Cell Biology, 2002Co-Authors: Shuang Tang, Wang-yi LiuAbstract:Eukaryotic elongation factor 2 (eEF2) catalyzed the translocation of peptidyl-tRNA from the ribosomal A site to the P site. In this paper, the interaction between eEF2 and GTD RNA, a synthetic oligoribonucleotide that mimicked the GTPase domain of rat 28S ribosomal RNA, was studied in vitro. The purified eEF2 could bind to GTD RNA, forming a stable complex. Transfer RNA competed with GTD RNA in binding to eEF2, whereas poly(A), poly(U) and poly(I, C) did not interfere with the interaction between eEF2 and GTD RNA, demonstrating that the tertiary structure of RNA might be necessary for the recognition of and binding to eEF2. The complex formation of eEF2 with GTD RNA was inhibited by SRD RNA, a synthetic oligoribonucleotide mimic of Sarcin/Ricin domain RNA of rat 28S RNA. Similarly, GTD RNA inhibited the interaction between eEF2 and SRD RNA. This fact implies that these small Oligoribonucleotides probably share similar recognition or binding identity elements in their tertiary structures. In addition, the binding of eEF2 to GTD RNA could be obviously weakened by the ADP-ribosylation of eEF2 with diphtheria toxin. These results indicate that eEF2 behaves differently from prokaryotic EF-G in binding to ribosomal RNA.
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eukaryotic elongation factor 2 can bind to the synthetic oligoribonucleotide that mimics sarcin ricin domain of rat 28s ribosomal rna
Molecular and Cellular Biochemistry, 2001Co-Authors: Shuang Tang, Wang-yi Liu, Kang-cheng RuanAbstract:Eukaryotic elongation factor 2 (eEF2) catalyzes the translocation of peptidyl-tRNA from the A site to P site by binding to the ribosome. In this work, the complex formation of rat liver eEF2 with a synthetic oligoribonucleotide (SRD RNA) that mimics sarcin/ricin domain of rat 28S ribosomal RNA is invested in vitro. Purified eEF2 can specifically bind SRD RNA to form a stable complex. tRNA competes with SRD RNA in binding to eEF2 in a less extent. Pretreatment of eEF2 with GDP or ADP-ribosylation of eEF2 by diphtheria toxin can obviously reduce the ability of eEF2 to form the complex with the synthetic oligoribonucleotide. These results indicate that eEF2 is likely to bind directly to the sarcin/ricin domain of 28S ribosomal RNA in the process of protein synthesis.
Shuang Tang - One of the best experts on this subject based on the ideXlab platform.
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In vitro interaction of eukaryotic elongation factor 2 with synthetic oligoribonucleotide that mimics GTPase domain of rat 28S ribosomal RNA.
The International Journal of Biochemistry & Cell Biology, 2002Co-Authors: Shuang Tang, Wang-yi LiuAbstract:Eukaryotic elongation factor 2 (eEF2) catalyzed the translocation of peptidyl-tRNA from the ribosomal A site to the P site. In this paper, the interaction between eEF2 and GTD RNA, a synthetic oligoribonucleotide that mimicked the GTPase domain of rat 28S ribosomal RNA, was studied in vitro. The purified eEF2 could bind to GTD RNA, forming a stable complex. Transfer RNA competed with GTD RNA in binding to eEF2, whereas poly(A), poly(U) and poly(I, C) did not interfere with the interaction between eEF2 and GTD RNA, demonstrating that the tertiary structure of RNA might be necessary for the recognition of and binding to eEF2. The complex formation of eEF2 with GTD RNA was inhibited by SRD RNA, a synthetic oligoribonucleotide mimic of Sarcin/Ricin domain RNA of rat 28S RNA. Similarly, GTD RNA inhibited the interaction between eEF2 and SRD RNA. This fact implies that these small Oligoribonucleotides probably share similar recognition or binding identity elements in their tertiary structures. In addition, the binding of eEF2 to GTD RNA could be obviously weakened by the ADP-ribosylation of eEF2 with diphtheria toxin. These results indicate that eEF2 behaves differently from prokaryotic EF-G in binding to ribosomal RNA.
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eukaryotic elongation factor 2 can bind to the synthetic oligoribonucleotide that mimics sarcin ricin domain of rat 28s ribosomal rna
Molecular and Cellular Biochemistry, 2001Co-Authors: Shuang Tang, Wang-yi Liu, Kang-cheng RuanAbstract:Eukaryotic elongation factor 2 (eEF2) catalyzes the translocation of peptidyl-tRNA from the A site to P site by binding to the ribosome. In this work, the complex formation of rat liver eEF2 with a synthetic oligoribonucleotide (SRD RNA) that mimics sarcin/ricin domain of rat 28S ribosomal RNA is invested in vitro. Purified eEF2 can specifically bind SRD RNA to form a stable complex. tRNA competes with SRD RNA in binding to eEF2 in a less extent. Pretreatment of eEF2 with GDP or ADP-ribosylation of eEF2 by diphtheria toxin can obviously reduce the ability of eEF2 to form the complex with the synthetic oligoribonucleotide. These results indicate that eEF2 is likely to bind directly to the sarcin/ricin domain of 28S ribosomal RNA in the process of protein synthesis.
Mitsuo Sekine - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of 2′-O-[2-(N-Methylcarbamoyl)ethyl]ribonucleosides Using Oxa-Michael Reaction and Chemical and Biological Properties of Oligonucleotide Derivatives Incorporating These Modified Ribonucleosides
2015Co-Authors: Takeshi Yamada, Natsuki Okaniwa, Hisao Saneyoshi, Akihiro Ohkubo, Yoshitsugu Aoki, Kohji Seio, Tetsuya Nagata, Shin’ichi Takeda, Mitsuo SekineAbstract:To develop oligonucleotides containing new 2′-O-modified ribonucleosides as nucleic acid drugs, we synthesized three types of ribonucleoside derivatives modified at the 2′-hydroxyl group with 2-(methoxycarbonyl)ethyl (MOCE), 2-(N-methylcarbamoyl)ethyl (MCE), and 2-(N,N-dimethylcarbamoyl)ethyl (DMCE) groups, as key intermediates, via the oxa-Michael reaction of the appropriately protected ribonucleoside (U, C, A, and G) derivatives. Among them, the 2′-O-MCE ribonucleosides were found to be the most stable under basic conditions. To study the effects of the 2′-O-modification on the nuclease resistance of oligonucleotides incorporating the 2′-O-modified ribonucleosides and their hybridization affinities for the complementary RNA and DNA strands, 2′-O-MCE-ribonucleoside phosphoramidite derivatives were successfully synthesized and subjected to the synthesis of 2′-O-MCE-oligonucleotides and 2′-O-methyl-oligonucleotides incorporating 2′-O-MCE-ribonucleosides. The 2′-O-MCE-oligonucleotides and chimeric oligomers with 2′-O-MCE and 2′-O-methyl groups thus obtained demonstrated complementary RNA strands and much higher nuclease resistances than the corresponding 2′-O-methylated species. Finally, we incorporated the 2′-O-MCE-ribonucleosides into antisense 2′-O-methyl-Oligoribonucleotides to examine their exon-skipping activities in splicing reactions related to pre-mRNA of mouse dystrophin. The exon-skipping assay of these 2′-O-methyl-oligonucleotide incorporating 2′-O-MCE-uridines showed better efficacies than the corresponding 2′-O-methylated oligoribonucleotide phosphorothioate derivatives
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Synthesis of 2'-O-[2-(N-methylcarbamoyl)ethyl]ribonucleosides using oxa-Michael reaction and chemical and biological properties of oligonucleotide derivatives incorporating these modified ribonucleosides.
Journal of Organic Chemistry, 2011Co-Authors: Takeshi Yamada, Natsuki Okaniwa, Hisao Saneyoshi, Akihiro Ohkubo, Yoshitsugu Aoki, Kohji Seio, Tetsuya Nagata, Shin-ichi Takeda, Mitsuo SekineAbstract:To develop oligonucleotides containing new 2'-O-modified ribonucleosides as nucleic acid drugs, we synthesized three types of ribonucleoside derivatives modified at the 2'-hydroxyl group with 2-(methoxycarbonyl)ethyl (MOCE), 2-(N-methylcarbamoyl)ethyl (MCE), and 2-(N,N-dimethylcarbamoyl)ethyl (DMCE) groups, as key intermediates, via the oxa-Michael reaction of the appropriately protected ribonucleoside (U, C, A, and G) derivatives. Among them, the 2'-O-MCE ribonucleosides were found to be the most stable under basic conditions. To study the effects of the 2'-O-modification on the nuclease resistance of oligonucleotides incorporating the 2'-O-modified ribonucleosides and their hybridization affinities for the complementary RNA and DNA strands, 2'-O-MCE-ribonucleoside phosphoramidite derivatives were successfully synthesized and subjected to the synthesis of 2'-O-MCE-oligonucleotides and 2'-O-methyl-oligonucleotides incorporating 2'-O-MCE-ribonucleosides. The 2'-O-MCE-oligonucleotides and chimeric oligomers with 2'-O-MCE and 2'-O-methyl groups thus obtained demonstrated complementary RNA strands and much higher nuclease resistances than the corresponding 2'-O-methylated species. Finally, we incorporated the 2'-O-MCE-ribonucleosides into antisense 2'-O-methyl-Oligoribonucleotides to examine their exon-skipping activities in splicing reactions related to pre-mRNA of mouse dystrophin. The exon-skipping assay of these 2'-O-methyl-oligonucleotide incorporating 2'-O-MCE-uridines showed better efficacies than the corresponding 2'-O-methylated oligoribonucleotide phosphorothioate derivatives.
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a general method for the synthesis of 2 o cyanoethylated Oligoribonucleotides having promising hybridization affinity for dna and rna and enhanced nuclease resistance
Journal of Organic Chemistry, 2005Co-Authors: Hisao Saneyoshi, Kohji Seio, Mitsuo SekineAbstract:An effective method for the synthesis of 2‘-O-cyanoethylated Oligoribonucleotides as a new class of 2‘-O-modified RNAs was developed. The reaction of appropriately protected ribonucleoside derivati...
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oligoribonucleotide synthesis by use of the 2 methylthio phenyl thio methyl mptm group as the 2 hydroxyl protecting group
ChemInform, 1992Co-Authors: Mitsuo Sekine, Takashi NakanishiAbstract:A new 2′-hydroxyl protecting group, [[2-(methylthio)phenyl]thio]methyl (MPTM), was introduced via a three-step reaction into the 2′-position of uridine and cytidine units required for the synthesis of Oligoribonucleotides in the phosphotriester approach. By using these monomer building blocks, CpUpG was synthesized.
