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Current Protocols in Nucleic Acid Chemistry

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https://www.readbyqxmd.com/read/28921499/synthesis-of-the-phosphoramidite-units-for-benzene-glycol-nucleic-acid
#1
Yusuke Maeda, Nazuki Niwa, Yoshihito Ueno
Benzene-glycol nucleic acid-DNA chimeras form thermally and thermodynamically stable duplexes with complementary RNAs, and have base-discriminating abilities. This unit describes the synthesis of four nucleoside analogs, an adenine, cytosine, thymine, and guanine analogs with base-benzene-glycol structure. The synthesis starts with conversion of (S)-mandelic acid in arylboronic acid derivative, common intermediate. Nucleobase coupling of the intermediate and phosphitylation afford to phosphoroamidite units...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921498/synthesis-of-4-selenoribonucleosides-the-building-blocks-of-4-selenorna-using-a-hypervalent-iodine
#2
Noriko Saito-Tarashima, Masashi Ota, Noriaki Minakawa
Herein is described a detailed protocol for the synthesis of 4'-selenoribonucleoside derivatives that involves the use of a hypervalent iodine species. These derivatives are versatile units for the preparation of 4'-selenoRNA. Large-scale synthesis of a 4-selenosugar starting from D-ribose is achieved in eight steps, including a final chromatographic purification. The resulting 4-selenosugar is then subjected to the one-pot Pummerer-like reaction using hypervalent iodine in the presence of silylated nucleobases...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921497/quantitative-analysis-of-nucleic-acid-stability-with-ligands-under-high-pressure-to-design-novel-drugs-targeting-g-quadruplexes
#3
Shuntaro Takahashi, Naoki Sugimoto
Nucleic acids (DNA and RNA) can form various non-canonical structures. Because some serious diseases are caused by the conformational change of G-quadruplex DNA structures, the development of ligands that bind and stabilize G-quadruplex DNA is of interest to the field of nucleic acid chemistry. Volumetric changes (ΔV) in the biomolecular reaction include the structural change of biomolecules and hydration behaviors, which provide information about the tertiary interaction between G-quadruplex DNA and ligands...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921496/nucleoside-o-methyl-h-phosphinates-novel-monomers-for-the-synthesis-of-methylphosphonate-oligonucleotides-using-h-phosphonate-chemistry
#4
Ondřej Kostov, Ondřej Páv, Ivan Rosenberg
This unit comprises the straightforward synthesis of protected 2'-deoxyribonucleoside-O-methyl-(H)-phosphinates in both 3'- and 5'-series. These compounds represent a new class of monomers compatible with the solid-phase synthesis of oligonucleotides using H-phosphonate chemistry and are suitable for the preparation of both 3'- and 5'-O-methylphosphonate oligonucleotides. The synthesis of 4-toluenesulfonyloxymethyl-(H)-phosphinic acid as a new reagent for the preparation of O-methyl-(H)-phosphinic acid derivatives is described...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921495/probing-rna-folding-pathways-by-rna-fingerprinting
#5
Sarah A Woodson
This unit provides protocols for using native polyacrylamide gel electrophoresis to distinguish folding and unfolding conformers of RNA. It is useful for studying conformers that can exchange in a period of minutes or seconds, and that are thus difficult to study by solution-based methods. Conformers that have been separated and immobilized in the gel matrix can be used to study catalytic activity with or without being eluted from the gel. The method can be applied to a wide variety of catalytic RNAs and RNA-protein complexes...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921494/solid-phase-synthesis-of-rna-analogs-containing-phosphorodithioate-linkages
#6
Xianbin Yang
The oligoribonucleotide phosphorodithioate (PS2-RNA) modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphorodiester backbone linkage. Like a natural phosphodiester RNA backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-RNAs are highly stable to nucleases and several in vitro assays have demonstrated their biological activity. For example, PS2-RNAs silenced mRNA in vitro and bound to protein targets in the form of PS2-aptamers (thioaptamers)...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28921493/vibration-ball-milling-for-the-synthesis-of-5-thioadenosine-5-pyrophosphate-p-%C3%A2-5-adenosine-dasppa
#7
Olga Eguaogie, Joseph S Vyle
Using vibration ball milling, 5'-chloro-5'-deoxyadenosine (CldA) reacts cleanly with 4-methoxybenzyl mercaptan (MobSH), under basic conditions, to the corresponding thioether (MobSdA), which is isolated following precipitation and trituration. Under acidic conditions, in a one-pot, two-step process, MobSdA is transformed into 5'-deoxy-5'-(5-nitropyridyl-2-disulfanyl)-adenosine (NPySSdA). Michaelis-Arbuzov (M-A) reaction of NPySSdA with tris(trimethylsilyl) phosphite proceeds to completion within 30 min as determined by (31) P NMR, and the persilylated M-A product thus formed can be stored in solution under anhydrous conditions at room temperature for several days (in contrast, the anionic phosphorothiolate monoester is labile to hydrolysis)...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628210/synthesis-of-oligodeoxynucleotides-containing-a-c8-2-deoxyguanosine-adduct-formed-by-the-carcinogen-3-nitrobenzanthrone
#8
Arindom Chatterjee, Chanchal K Malik, Ashis K Basu
This unit describes the detailed procedure in five parts for the synthesis of the C8-2'-deoxyguanosine-3-aminobenzanthrone adduct located in a desired site in an oligonucleotide. The synthesis of the protected 2'-deoxyguanosine, O(6) -benzyl-N(2) -DMTr-3'-5'-bisTBDMS-C8-Br-2'-deoxyguanosine, is described in the first part. The synthesis of the reduced carcinogen 3-aminobenzanthrone is detailed in part two. The third part outlines the key step of the adduct formation between the reduced carcinogen and the protected nucleoside by a palladium-catalyzed cross coupling reaction...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628209/nucleobase-protection-of-deoxyribo-and-ribonucleosides
#9
Geeta Meher, Nabin K Meher, Radhakrishnan P Iyer
Oligonucleotides carrying a variety of chemical modifications including conjugates are finding increasing applications in therapeutics, diagnostics, functional genomics, proteomics, and as research tools in chemical and molecular biology. The successful synthesis of oligonucleotides primarily depends on the use of appropriately protected nucleoside building blocks including the exocyclic amino groups of the nucleobases, the hydroxyl groups at the 2'-, 3'-, and 5'-positions of the sugar moieties, and the internucleotide phospho-linkage...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628208/carbocyclic-c-c-bond-formation-intramolecular-radical-ring-closure-to-yield-diastereomerically-pure-7-s-me-or-7-r-me-carba-lna-nucleotide-analogs
#10
Oleksandr Plashkevych, Ram Shankar Upadhayaya, Jyoti Chattopadhyaya
In light of the impressive gene-silencing properties of carba-LNA modified oligo DNA and RNA, both in antisense RNA and siRNA approaches, which have been confirmed as proof-of-concept for biochemical applications in post-transcriptional gene silencing, we envision the true potential of carba-LNA modifications to be revealed soon. Herein we provide detailed protocols for synthesis of carba-LNA-A, -G, -(5-Me) C, and -T nucleosides on a medium/large scale (gram scale), as well as important guidelines for incorporation of these modified carba-LNAs into DNA or RNA oligonucleotides...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628207/engineered-polymerases-with-altered-substrate-specificity-expression-and-purification
#11
Ali Nikoomanzar, Matthew R Dunn, John C Chaput
Polymerase engineering is making it possible to synthesize xeno-nucleic acid polymers (XNAs) with diverse backbone structures and chemical functionality. The ability to copy genetic information back and forth between DNA and XNA has led to a new field of science known as synthetic genetics, which aims to study the genetic concepts of heredity and evolution in artificial genetic polymers. Since many of the polymerases needed to synthesize XNA polymers are not available commercially, researchers must express and purify these enzymes as recombinant proteins from E...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628206/water-medium-synthesis-of-nucleoside-5-polyphosphates
#12
Anaïs Depaix, Suzanne Peyrottes, Béatrice Roy
This unit describes a one-pot, two step synthesis of ribonucleoside 5'-di- and 5'-triphosphates, as well as their purification. The first step of the synthesis involves the activation of an unprotected ribonucleoside 5'-monophosphate with 2-chloro-1,3-dimethylimidazolinium hexafluorophosphate and imidazole, in a mixture of water/acetonitrile. The resulting phosphorimidazolate intermediate is then treated with inorganic phosphate or pyrophosphate to afford the corresponding nucleoside 5'-di- or 5'-triphosphates...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628205/stereoselective-synthesis-of-4-selenonucleosides-via-the-seleno-michael-reaction
#13
Pramod K Sahu, Dnyandev B Jarhad, Gyudong Kim, Lak Shin Jeong
5'-Homo-4'-selenonucleosides, a class of next-generation nucleosides, are synthesized from D-ribose via a 4-selenosugar intermediate. The key step in synthesizing this intermediate is a seleno-Michael reaction. 5'-Homo-4'-selenouridine and -adenosine are prepared using Pummerer-type and Vorbrüggen condensation, respectively. © 2017 by John Wiley & Sons, Inc.
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28628204/a-high-throughput-process-for-the-solid-phase-purification-of-synthetic-dna-sequences
#14
Andrzej Grajkowski, Jacek Cieślak, Serge L Beaucage
An efficient process for the purification of synthetic phosphorothioate and native DNA sequences is presented. The process is based on the use of an aminopropylated silica gel support functionalized with aminooxyalkyl functions to enable capture of DNA sequences through an oximation reaction with the keto function of a linker conjugated to the 5'-terminus of DNA sequences. Deoxyribonucleoside phosphoramidites carrying this linker, as a 5'-hydroxyl protecting group, have been synthesized for incorporation into DNA sequences during the last coupling step of a standard solid-phase synthesis protocol executed on a controlled pore glass (CPG) support...
June 19, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252184/using-morpholinos-to-control-gene-expression
#15
Jon D Moulton
Morpholino oligonucleotides are stable, uncharged, water-soluble molecules used to block complementary sequences of RNA, preventing processing, read-through, or protein binding at those sites. Morpholinos are typically used to block translation of mRNA and to block splicing of pre-mRNA, though they can block other interactions between biological macromolecules and RNA. Morpholinos are effective, specific, and lack non-antisense effects. They work in any cell that transcribes and translates RNA, but must be delivered into the nuclear/cytosolic compartment to be effective...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252183/2-pyridinyl-thermolabile-groups-as-general-protectants-for-hydroxyl-phosphate-and-carboxyl-functions
#16
Jolanta Brzezinska, Agnieszka Witkowska, Tomasz P Kaczyński, Dominika Krygier, Tomasz Ratajczak, Marcin K Chmielewski
Application of 2-pyridinyl thermolabile protecting groups (2-PyTPGs) for protection of hydroxyl, phosphate, and carboxyl functions is presented in this unit. Their characteristic feature is a unique removal process following the intramolecular cyclization mechanism and induced only by temperature rise. Deprotection rate of 2-PyTPGs is dependent on certain parameters, such as solvent (aqueous or non-aqueous medium), pH values, and electron distribution in a pyridine ring. The presented approach pertains not only to protecting groups but also to an advanced system of controlling certain properties of 2-pyridinyl derivatives...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252182/synthesis-of-geranyl-2-thiouridine-modified-rna
#17
Rui Wang, Phensinee Haruehanroengra, Jia Sheng
This unit describes the chemical synthesis of the S-geranyl-2-thiouridine (ges(2) U) phosphoramidite and its incorporation into RNA oligonucleotides through solid-phase synthesis. Starting from the 2-thiouracil nucleobase and the protected ribose, the 2-thiouridine is synthesized and the geranyl functionality is introduced into the 2-thio position by using geranyl bromide as the geranylating reagent before the conversion of this modified nucleoside into a phosphoramidite building block. The modified phosphoramidite is used to make the geranyl-RNA oligonucleotides with a solid-phase DNA synthesizer...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252181/characterization-of-quadruplex-dna-structure-by-circular-dichroism
#18
Rafael Del Villar-Guerra, Robert D Gray, Jonathan B Chaires
Circular dichroism (CD) is a phenomenon that arises from the differential absorption of left- and right-handed circularly polarized light, and may be seen with optically active molecules. CD spectroscopy provides useful spectral signatures for biological macromolecules in solution, and provides low-resolution structural information about macromolecular conformation. CD spectroscopy is particularly useful for monitoring conformational changes in macromolecules upon environmental perturbations. G-quadruplex structures show unique CD spectral signatures, and CD is an important tool for characterizing their formation and global structure...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252180/facile-access-to-bromonucleosides-using-sodium-monobromoisocyanurate-smbi
#19
Jyotirmoy Maity, Smriti Srivastava, Yogesh S Sanghvi, Ashok K Prasad, Roger Stromberg
Bromonucleosides constitute a significant class of molecules and are well known for their biological activity. 5-Bromouridine, 5-bromo-2'-deoxyuridine, 5-bromouridine-5'-triphosphate, and nucleotides containing 5-bromouridine have been tested and used for numerous biological studies. 8-Bromopurine nucleosides have been used as essential precursors for the synthesis of nucleosides with fluorescent properties. This unit describes protocols for the synthesis of bromonucleosides using sodium monobromoisocyanurate (SMBI) in a straightforward way...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28252179/deformability-calculation-for-estimation-of-the-relative-stability-of-chemically-modified-rna-duplexes
#20
Yoshiaki Masaki, Mitsuo Sekine, Kohji Seio
Chemical modification of RNA duplexes alters their stability. We have attempted to develop a computational approach to estimate the thermal stability of chemically modified duplexes. These studies revealed that the deformability of chemically modified RNA duplexes, calculated from molecular dynamics simulations, could be used as a good indicator for estimating the effect of chemical modification on duplex thermal stability. This unit describes how deformability calculation can be applied to estimate the relative stability of chemically modified RNA duplexes...
March 2, 2017: Current Protocols in Nucleic Acid Chemistry
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