The Experts below are selected from a list of 42744 Experts worldwide ranked by ideXlab platform
Heinz G. Floss - One of the best experts on this subject based on the ideXlab platform.
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Overexpression of the Thiostrepton‐resistance Gene from Streptomyces azureus in Escherichia coli and Characterization of Recognition sites of the 23S rRNA A1067 2′‐methyltransferase in the Guanosine Triphosphatase Center of 23S Ribosomal RNA
European journal of biochemistry, 1994Co-Authors: Andreas Bechthold, Heinz G. FlossAbstract:The thiostrepton-resistance gene encoding the 23S rRNA A1067 methyltransferase from Streptomyces azureus has been overexpressed in Escherichia coli using a T7-RNA-polymerase-dependent expression vector. The protein was efficiently expressed at levels up to 20% of total soluble protein and purified to near homogeneity. Kinetic parameters for S-adenosyl-l-methionine (Km= 0.1 mM) and an RNA fragment containing nucleotides 1029–1122 of the 23S Ribosomal RNA from E. coli (Km= 0.001 mM) were determined. S-Adenosyl-l-homocysteine showed competitive product inhibition (Ki= 0.013 mM). Binding of either thiostrepton or protein L11 inhibited methylation. RNA sequence variants of the RNA fragment with mutations in nucleotides 1051–1108 were tested as substrates for the methylase. The experimental data indicate that methylation is dependent on the secondary structure of the hairpin including nucleotide A1067 and the exact sequence U(1066)-A(1067)-G(1068)-A(1069)-A(1070) of the single strand.
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overexpression of the thiostrepton resistance gene from streptomyces azureus in escherichia coli and characterization of recognition sites of the 23S rRNA a1067 2 methyltransferase in the guanosine triphosphatase center of 23S Ribosomal RNA
FEBS Journal, 1994Co-Authors: Andreas Bechthold, Heinz G. FlossAbstract:The thiostrepton-resistance gene encoding the 23S rRNA A1067 methyltransferase from Streptomyces azureus has been overexpressed in Escherichia coli using a T7-RNA-polymerase-dependent expression vector. The protein was efficiently expressed at levels up to 20% of total soluble protein and purified to near homogeneity. Kinetic parameters for S-adenosyl-l-methionine (Km= 0.1 mM) and an RNA fragment containing nucleotides 1029–1122 of the 23S Ribosomal RNA from E. coli (Km= 0.001 mM) were determined. S-Adenosyl-l-homocysteine showed competitive product inhibition (Ki= 0.013 mM). Binding of either thiostrepton or protein L11 inhibited methylation. RNA sequence variants of the RNA fragment with mutations in nucleotides 1051–1108 were tested as substrates for the methylase. The experimental data indicate that methylation is dependent on the secondary structure of the hairpin including nucleotide A1067 and the exact sequence U(1066)-A(1067)-G(1068)-A(1069)-A(1070) of the single strand.
Andreas Bechthold - One of the best experts on this subject based on the ideXlab platform.
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Overexpression of the Thiostrepton‐resistance Gene from Streptomyces azureus in Escherichia coli and Characterization of Recognition sites of the 23S rRNA A1067 2′‐methyltransferase in the Guanosine Triphosphatase Center of 23S Ribosomal RNA
European journal of biochemistry, 1994Co-Authors: Andreas Bechthold, Heinz G. FlossAbstract:The thiostrepton-resistance gene encoding the 23S rRNA A1067 methyltransferase from Streptomyces azureus has been overexpressed in Escherichia coli using a T7-RNA-polymerase-dependent expression vector. The protein was efficiently expressed at levels up to 20% of total soluble protein and purified to near homogeneity. Kinetic parameters for S-adenosyl-l-methionine (Km= 0.1 mM) and an RNA fragment containing nucleotides 1029–1122 of the 23S Ribosomal RNA from E. coli (Km= 0.001 mM) were determined. S-Adenosyl-l-homocysteine showed competitive product inhibition (Ki= 0.013 mM). Binding of either thiostrepton or protein L11 inhibited methylation. RNA sequence variants of the RNA fragment with mutations in nucleotides 1051–1108 were tested as substrates for the methylase. The experimental data indicate that methylation is dependent on the secondary structure of the hairpin including nucleotide A1067 and the exact sequence U(1066)-A(1067)-G(1068)-A(1069)-A(1070) of the single strand.
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overexpression of the thiostrepton resistance gene from streptomyces azureus in escherichia coli and characterization of recognition sites of the 23S rRNA a1067 2 methyltransferase in the guanosine triphosphatase center of 23S Ribosomal RNA
FEBS Journal, 1994Co-Authors: Andreas Bechthold, Heinz G. FlossAbstract:The thiostrepton-resistance gene encoding the 23S rRNA A1067 methyltransferase from Streptomyces azureus has been overexpressed in Escherichia coli using a T7-RNA-polymerase-dependent expression vector. The protein was efficiently expressed at levels up to 20% of total soluble protein and purified to near homogeneity. Kinetic parameters for S-adenosyl-l-methionine (Km= 0.1 mM) and an RNA fragment containing nucleotides 1029–1122 of the 23S Ribosomal RNA from E. coli (Km= 0.001 mM) were determined. S-Adenosyl-l-homocysteine showed competitive product inhibition (Ki= 0.013 mM). Binding of either thiostrepton or protein L11 inhibited methylation. RNA sequence variants of the RNA fragment with mutations in nucleotides 1051–1108 were tested as substrates for the methylase. The experimental data indicate that methylation is dependent on the secondary structure of the hairpin including nucleotide A1067 and the exact sequence U(1066)-A(1067)-G(1068)-A(1069)-A(1070) of the single strand.
Suyeon Park - One of the best experts on this subject based on the ideXlab platform.
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cost effectiveness of a tailored helicobacter pylori eradication strategy based on the presence of a 23S Ribosomal RNA point mutation that causes clarithromycin resistance in korean patients
Journal of Gastroenterology and Hepatology, 2019Co-Authors: Jun-hyung Cho, Seong Ran Jeon, Hyun Gun Kim, So-young Jin, Suyeon ParkAbstract:BACKGROUND AND AIM The Helicobacter pylori eradication rate using conventional triple therapy has decreased due to clarithromycin (CAM) resistance in H. pylori. Recently, dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) can be used to detect H. pylori and point mutations in the 23S Ribosomal RNA gene causing CAM resistance. This study aimed to evaluate the success rate and cost-effectiveness of tailored H. pylori eradication using DPO-PCR. METHODS The H. pylori-positive patients diagnosed by a rapid urease test or DPO-PCR were enrolled from a single academic hospital. The patients with positive rapid urease test results received a CAM-based triple regimen. In the tailored therapy group that underwent DPO-PCR testing, patients with A2142G and/or A2143G point mutations were treated with a bismuth-containing quadruple regimen. The cost-effectiveness of H. pylori eradication success was evaluated according to the average cost per patient and the incremental cost-effectiveness ratio. RESULTS A total of 243 patients were allocated to the triple therapy group and 124 patients to the tailored therapy group. The first-line eradication rate of H. pylori was significantly higher in the tailored therapy group than in the conventional triple therapy group (92.7% vs 76.5%, P < 0.001). The average costs per patient for tailored therapy were $307.37 and $299.59 for first-line and second-line treatments, respectively. Compared with triple therapy, the incremental cost-effectiveness ratios of tailored therapy were $3.96 and -$3.81 per patient for first-line and second-line treatments, respectively. CONCLUSION In Korea, tailored H. pylori eradication using DPO-PCR may be more cost-effective than conventional triple therapy.
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Cost-effectiveness of a tailored Helicobacter pylori eradication strategy based on the presence of a 23S Ribosomal RNA point mutation that causes clarithromycin resistance in Korean patients.
Journal of gastroenterology and hepatology, 2018Co-Authors: Jun-hyung Cho, Seong Ran Jeon, Hyun Gun Kim, So-young Jin, Suyeon ParkAbstract:BACKGROUND AND AIM The Helicobacter pylori eradication rate using conventional triple therapy has decreased due to clarithromycin (CAM) resistance in H. pylori. Recently, dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) can be used to detect H. pylori and point mutations in the 23S Ribosomal RNA gene causing CAM resistance. This study aimed to evaluate the success rate and cost-effectiveness of tailored H. pylori eradication using DPO-PCR. METHODS The H. pylori-positive patients diagnosed by a rapid urease test or DPO-PCR were enrolled from a single academic hospital. The patients with positive rapid urease test results received a CAM-based triple regimen. In the tailored therapy group that underwent DPO-PCR testing, patients with A2142G and/or A2143G point mutations were treated with a bismuth-containing quadruple regimen. The cost-effectiveness of H. pylori eradication success was evaluated according to the average cost per patient and the incremental cost-effectiveness ratio. RESULTS A total of 243 patients were allocated to the triple therapy group and 124 patients to the tailored therapy group. The first-line eradication rate of H. pylori was significantly higher in the tailored therapy group than in the conventional triple therapy group (92.7% vs 76.5%, P
Jun-hyung Cho - One of the best experts on this subject based on the ideXlab platform.
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cost effectiveness of a tailored helicobacter pylori eradication strategy based on the presence of a 23S Ribosomal RNA point mutation that causes clarithromycin resistance in korean patients
Journal of Gastroenterology and Hepatology, 2019Co-Authors: Jun-hyung Cho, Seong Ran Jeon, Hyun Gun Kim, So-young Jin, Suyeon ParkAbstract:BACKGROUND AND AIM The Helicobacter pylori eradication rate using conventional triple therapy has decreased due to clarithromycin (CAM) resistance in H. pylori. Recently, dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) can be used to detect H. pylori and point mutations in the 23S Ribosomal RNA gene causing CAM resistance. This study aimed to evaluate the success rate and cost-effectiveness of tailored H. pylori eradication using DPO-PCR. METHODS The H. pylori-positive patients diagnosed by a rapid urease test or DPO-PCR were enrolled from a single academic hospital. The patients with positive rapid urease test results received a CAM-based triple regimen. In the tailored therapy group that underwent DPO-PCR testing, patients with A2142G and/or A2143G point mutations were treated with a bismuth-containing quadruple regimen. The cost-effectiveness of H. pylori eradication success was evaluated according to the average cost per patient and the incremental cost-effectiveness ratio. RESULTS A total of 243 patients were allocated to the triple therapy group and 124 patients to the tailored therapy group. The first-line eradication rate of H. pylori was significantly higher in the tailored therapy group than in the conventional triple therapy group (92.7% vs 76.5%, P < 0.001). The average costs per patient for tailored therapy were $307.37 and $299.59 for first-line and second-line treatments, respectively. Compared with triple therapy, the incremental cost-effectiveness ratios of tailored therapy were $3.96 and -$3.81 per patient for first-line and second-line treatments, respectively. CONCLUSION In Korea, tailored H. pylori eradication using DPO-PCR may be more cost-effective than conventional triple therapy.
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Cost-effectiveness of a tailored Helicobacter pylori eradication strategy based on the presence of a 23S Ribosomal RNA point mutation that causes clarithromycin resistance in Korean patients.
Journal of gastroenterology and hepatology, 2018Co-Authors: Jun-hyung Cho, Seong Ran Jeon, Hyun Gun Kim, So-young Jin, Suyeon ParkAbstract:BACKGROUND AND AIM The Helicobacter pylori eradication rate using conventional triple therapy has decreased due to clarithromycin (CAM) resistance in H. pylori. Recently, dual priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) can be used to detect H. pylori and point mutations in the 23S Ribosomal RNA gene causing CAM resistance. This study aimed to evaluate the success rate and cost-effectiveness of tailored H. pylori eradication using DPO-PCR. METHODS The H. pylori-positive patients diagnosed by a rapid urease test or DPO-PCR were enrolled from a single academic hospital. The patients with positive rapid urease test results received a CAM-based triple regimen. In the tailored therapy group that underwent DPO-PCR testing, patients with A2142G and/or A2143G point mutations were treated with a bismuth-containing quadruple regimen. The cost-effectiveness of H. pylori eradication success was evaluated according to the average cost per patient and the incremental cost-effectiveness ratio. RESULTS A total of 243 patients were allocated to the triple therapy group and 124 patients to the tailored therapy group. The first-line eradication rate of H. pylori was significantly higher in the tailored therapy group than in the conventional triple therapy group (92.7% vs 76.5%, P
Marco V Jose - One of the best experts on this subject based on the ideXlab platform.
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the ancient history of peptidyl transferase center formation as told by conservation and information analyses
Life, 2020Co-Authors: Francisco Prosdocimi, Sávio Torres De Farias, Gabriel S Zamudio, Miryam Palaciosperez, Marco V JoseAbstract:The peptidyl transferase center (PTC) is the catalytic center of the ribosome and forms part of the 23S Ribosomal RNA. The PTC has been recognized as the earliest Ribosomal part and its origins embodied the First Universal Common Ancestor (FUCA). The PTC is frequently assumed to be highly conserved along all living beings. In this work, we posed the following questions: (i) How many 100% conserved bases can be found in the PTC? (ii) Is it possible to identify clusters of informationally linked nucleotides along its sequence? (iii) Can we propose how the PTC was formed? (iv) How does sequence conservation reflect on the secondary and tertiary structures of the PTC? Aiming to answer these questions, all available complete sequences of 23S Ribosomal RNA from Bacteria and Archaea deposited on GenBank database were downloaded. Using a sequence bait of 179 bp from the PTC of Thermus termophilus, we performed an optimum pairwise alignment to retrieve the PTC region from 1424 filtered 23S rRNA sequences. These PTC sequences were multiply aligned, and the conserved regions were assigned and observed along the primary, secondary, and tertiary structures. The PTC structure was observed to be more highly conserved close to the adenine located at the catalytical site. Clusters of interrelated, co-evolving nucleotides reinforce previous assumptions that the PTC was formed by the concatenation of proto-tRNAs and important residues responsible for its assembly were identified. The observed sequence variation does not seem to significantly affect the 3D structure of the PTC ribozyme.
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origin and evolution of the peptidyl transferase center from proto tRNAs
FEBS Open Bio, 2014Co-Authors: Sávio Torres De Farias, Thaís Gaudencio Do Rêgo, Marco V JoseAbstract:We tested the hypothesis of Tamura (2011) [3] that molecules of tRNA gave origin to ribosomes, particularly to the Peptidyl Transferase Center (PTC) of the 23S Ribosomal RNA. We reconstructed the ancestral sequences from all types of tRNA and compared them in their sequences with the current PTC of 23S Ribosomal RNA from different organisms. We built an ancestral sequence of proto-tRNAs that showed a remarkable overall identity of 50.53% with the catalytic site of PTC. We conclude that the Peptidyl Transferase Center was indeed originated by the fusion of ancestral sequences of proto-tRNA.
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Origin and evolution of the Peptidyl Transferase Center from proto‐tRNAs
FEBS Open Bio, 2014Co-Authors: Sávio Torres De Farias, Thaís Gaudencio Do Rêgo, Marco V JoseAbstract:We tested the hypothesis of Tamura (2011) [3] that molecules of tRNA gave origin to ribosomes, particularly to the Peptidyl Transferase Center (PTC) of the 23S Ribosomal RNA. We reconstructed the ancestral sequences from all types of tRNA and compared them in their sequences with the current PTC of 23S Ribosomal RNA from different organisms. We built an ancestral sequence of proto-tRNAs that showed a remarkable overall identity of 50.53% with the catalytic site of PTC. We conclude that the Peptidyl Transferase Center was indeed originated by the fusion of ancestral sequences of proto-tRNA.