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Frank Seela - One of the best experts on this subject based on the ideXlab platform.
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Ethynyl Side Chain Hydration during Synthesis and Workup of “Clickable” Oligonucleotides: Bypassing Acetyl Group Formation by Triisopropylsilyl Protection
The Journal of organic chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.
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ethynyl side chain hydration during synthesis and workup of clickable oligonucleotides bypassing Acetyl Group formation by triisopropylsilyl protection
Journal of Organic Chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.
Peter Biely - One of the best experts on this subject based on the ideXlab platform.
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Positional specificity of Flavobacterium johnsoniae Acetylxylan esterase and Acetyl Group migration on xylan main chain.
Carbohydrate polymers, 2019Co-Authors: Vladimír Puchart, Morten Gjermansen, Mária Mastihubová, Kristian B. R. M. Krogh, Peter BielyAbstract:A new Flavovacterium johnsoniae isolate encodes an enzyme that is essentially identical with a recently discovered novel Acetylxylan esterase, capable of liberating 3-O-Acetyl Group from 4-O-methyl-d-glucuronic acid-substituted xylopyranosyl (Xylp) residues (Razeq et al., 2018). In addition to deesterification of the 2-O-MeGlcA-substituted Xylp residues in Acetylglucuronoxylan, the enzyme acts equally well on doubly Acetylated Xylp residues from which it liberates only the 3-O-Acetyl Groups, leaving the 2-O-Acetyl Groups untouched. 3-O-MonoAcetylated Xylp residues are attacked with a significantly reduced affinity. The resulting 2-O-Acetylated xylan was used to investigate for the first time the migration of the 2-O-Acetyl Group to position 3 within the polysaccharide. In contrast to easy Acetyl Group migration along the monomeric xylopyranosides or non-reducing-end terminal Xylp residues of xylooligosaccharides, such a migration in the polymer required much longer heating at 100 °C. The specificity of the xylan 3-O-deAcetylase was, however, no so strict on Acetylated methyl and 4-nitrophenyl xylopyranosides.
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Redistribution of Acetyl Groups on the non-reducing end xylopyranosyl residues and their removal by xylan deAcetylases
Applied microbiology and biotechnology, 2014Co-Authors: Vladimír Puchart, Peter BielyAbstract:Background MonoAcetylated xylosyl residues of the main hardwood hemicellulose Acetylglucuronoxylan undergo Acetyl Group migration between positions 2 and 3, and predominantly to position 4 of the non-reducing end xylopyranosyl (NRE-Xylp) residues which are amplified by saccharifying enzymes. On monoAcetylated non-reducing end xylopyranosyl (NRE-Xylp) residues of xylooligosaccharides the Acetyl Group migrates predominantly to position 4 and hinders their hydrolysis by β-xylosidase.
Sachin A. Ingale - One of the best experts on this subject based on the ideXlab platform.
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Ethynyl Side Chain Hydration during Synthesis and Workup of “Clickable” Oligonucleotides: Bypassing Acetyl Group Formation by Triisopropylsilyl Protection
The Journal of organic chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.
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ethynyl side chain hydration during synthesis and workup of clickable oligonucleotides bypassing Acetyl Group formation by triisopropylsilyl protection
Journal of Organic Chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.
Vladimír Puchart - One of the best experts on this subject based on the ideXlab platform.
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Positional specificity of Flavobacterium johnsoniae Acetylxylan esterase and Acetyl Group migration on xylan main chain.
Carbohydrate polymers, 2019Co-Authors: Vladimír Puchart, Morten Gjermansen, Mária Mastihubová, Kristian B. R. M. Krogh, Peter BielyAbstract:A new Flavovacterium johnsoniae isolate encodes an enzyme that is essentially identical with a recently discovered novel Acetylxylan esterase, capable of liberating 3-O-Acetyl Group from 4-O-methyl-d-glucuronic acid-substituted xylopyranosyl (Xylp) residues (Razeq et al., 2018). In addition to deesterification of the 2-O-MeGlcA-substituted Xylp residues in Acetylglucuronoxylan, the enzyme acts equally well on doubly Acetylated Xylp residues from which it liberates only the 3-O-Acetyl Groups, leaving the 2-O-Acetyl Groups untouched. 3-O-MonoAcetylated Xylp residues are attacked with a significantly reduced affinity. The resulting 2-O-Acetylated xylan was used to investigate for the first time the migration of the 2-O-Acetyl Group to position 3 within the polysaccharide. In contrast to easy Acetyl Group migration along the monomeric xylopyranosides or non-reducing-end terminal Xylp residues of xylooligosaccharides, such a migration in the polymer required much longer heating at 100 °C. The specificity of the xylan 3-O-deAcetylase was, however, no so strict on Acetylated methyl and 4-nitrophenyl xylopyranosides.
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Redistribution of Acetyl Groups on the non-reducing end xylopyranosyl residues and their removal by xylan deAcetylases
Applied microbiology and biotechnology, 2014Co-Authors: Vladimír Puchart, Peter BielyAbstract:Background MonoAcetylated xylosyl residues of the main hardwood hemicellulose Acetylglucuronoxylan undergo Acetyl Group migration between positions 2 and 3, and predominantly to position 4 of the non-reducing end xylopyranosyl (NRE-Xylp) residues which are amplified by saccharifying enzymes. On monoAcetylated non-reducing end xylopyranosyl (NRE-Xylp) residues of xylooligosaccharides the Acetyl Group migrates predominantly to position 4 and hinders their hydrolysis by β-xylosidase.
Hui Mei - One of the best experts on this subject based on the ideXlab platform.
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Ethynyl Side Chain Hydration during Synthesis and Workup of “Clickable” Oligonucleotides: Bypassing Acetyl Group Formation by Triisopropylsilyl Protection
The Journal of organic chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.
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ethynyl side chain hydration during synthesis and workup of clickable oligonucleotides bypassing Acetyl Group formation by triisopropylsilyl protection
Journal of Organic Chemistry, 2013Co-Authors: Sachin A. Ingale, Hui Mei, Peter Leonard, Frank SeelaAbstract:Clickable oligonucleotides with ethynyl residues in the 5-position of pyrimidines (ethdC and ethdU) or the 7-position of 7-deazaguanine (ethc7Gd) are hydrated during solid-phase oligonucleotide synthesis and workup conditions. The side products were identified as Acetyl derivatives by MALDI-TOF mass spectra of oligonucleotides and by detection of modified nucleosides after enzymatic phosphodiester hydrolysis. Ethynyl → Acetyl Group conversion was also studied on ethynylated nucleosides under acidic and basic conditions. It could be shown that side chain conversion depends on the nucleobase structure. Triisopropylsilyl residues were introduced to protect ethynyl residues from hydration. Pure, Acetyl Group free oligonucleotides were isolated after desilylation in all cases.