Isolation of 2′-O-methylribonucleoside 5′-phosphates and their properties as enzymic substrates

With the Technical Assistance of Gladys M. Keddy ABSTRACT: 02/-Methylpseudouridine (i/m) has been identified as a constituent of wheat embryo cytosol rRNA. The corresponding 5'-nucleotide, p\fm, was recovered from snake venom hydrolysates of the 18S + 26S ribonucleates of wheat embryo. The identity of this nucleotide was established by its ultraviolet absorption spectra, chromatographic and electrophoretic properties, and conversion to i/'m by treatment with alkaline phosphatase. Control experiments have eliminated the possibility that contaminating tRNA could have been the source of the p\pm isolated from wheat embryo 18S + 26S rRNA. Alkaline hydrolysis of 18S + 26S rRNA released ipm in the form of an alkali-stable dinucleotide, ^m-Ap. Since the quantity of i/'in-Ap in alkaline hydrolysates (0.016 mol %) was equal to the amount of p^m found in venom hydrolysates (0.017 mol %), all of the \pm in wheat embryo 18S + 26S rRN A is apparently coni. he ribosomal RNA (rRNA) of various organisms is known to contain a small proportion of methylated nucleoside components,1 in which methyl groups are located either on the base or on the sugar (at the O2 ***' position) or on both (Attardi and Amaldi, 1970). Extensive analysis of the alkali-stable diand trinucleotide sequences of rRNA from a variety of organisms (Singh and Lane, 1964;Lane, 1965;

Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Presence of O^2'-methylpseudouridine in the 18S + 26S ribosomal ribonucleates of wheat embryo

Gray¹,

Keddy²

1974

“…Thus the 2'-0-methyl group is a unit of considerable interest and versatility in the chemistry and binding of nucleic acid structures. It has been reported that the 2'-0-methyl nucleoside derivatives differ significantly from the corresponding nucleoside derivatives in being resistant to hydrolase and phosphorylase enzymes (Honjo et al, 1964;Hudson et al, 1965). Glycosidic bond cleavage is an important mechanism (Heidelberger, 1965) in the cross-resistance of a biochemically active base and its nucleoside and thus the synthesis of 2 '-0methyl nucleosides of active bases is also a significant area for investigation.…”

mentioning

confidence: 99%

“…In view of the altered enzymatic properties reported for 2'-0-methyl nucleoside derivatives (Honjo et al, 1964;Hudson et al, 1965), the investigation of 5-halo-2'-0-methyluridines is of significant interest. Treatment of 2'-0-methyluridine (5) (Scheme II) or alternatively 4-methoxy-l -(2-0-methyl-/3-Dribofuranosyl)-2-pyrimidinone (2) with chlorine in acetic acid-carbon tetrachloride (Prystas and Sorm, 1964) gave 5chloro-2'-O-methyluridine (11) in excellent yield.…”

mentioning

confidence: 99%

Nucleic acid related compounds. 1. Methylation and transformation of 4-methoxy-2-pyrimidinone 1-β-D-ribofuranoside into 2'-O-methyl nucleoside components of ribonucleic acid, their analogs, and derivatives

Robins¹,

Naik²

1971

Methylation of 4-methoxy-1 -/3-D-ribof uranosyl-2pyrimidinone (1) with diazomethane gave 4-methoxy-l -(2-0methyl-/3-D-ribofuranosyl)-2-pyrimidinone (2), 4-methoxy-1-(3-0-methyl-/3-D-ribofuranosyl)-2-pyrimidinone (3), and 4-methoxy-l-(2,3-di-0-methyl-/3-D-ribofuranosyl)-2-pyrimidinone (4). The pure 2'-0-methyl product (2) was isolated in 37 % yield under selected conditions. Acid hydrolysis of 2 gave 2 '-O-methyluridine (5) whereas nucleophilic displacement of the 4-methoxyl function by ammonia or methylamine gave 2 '-0-methylcytidine ( 7) and the new RNA minor component wish to report a general procedure for the synthesis of 2'-0-methyl nucleosides of 4-substituted 2-pyrimidinones. The 3'-0-methyl and 2',3'-di-0-methyl derivatives can also be obtained from the reaction mixture.Numerous reports (see, for example, Smith and Dunn, 1959, Hall, 1964, Tamaoki and Lane, 1968, Lane and Tamaoki 1969, and references therein) have appeared concerning the

“…They again confirmed that the base has far less inhibitory activity than the nucleoside in this mammalian system. It has been reported (Honjo et al, 1964) that certain 2 '-O-methyl nucleosides are inert to the action of hydrolase and phosphorylase enzymes. Since 3'-<9methyluridine is also apparently inert to the action of uridine phosphorylase (Furukawa et al, 1965), the 2'-O-methyl (3a) and 3 '-O-methyl (3b) iPA derivatives represent logical candidates to evaluate against this type of biochemically resistant cell (Robins and Naik, 1971a) and as anticytokinins (Hecht et al, 1971b).…”

mentioning

confidence: 99%

Nucleic acid related compounds. 6. Sugar-modified N⁶-(3-methyl-2-butenyl)adenosine derivatives, N⁶-benzyl analogs, and cytokinin-related nucleosides containing sulfur or formycin

Robins¹,

Trip²

1973

Nucleoside analogs of lV6-(3-methyl-2-butenyl)adenosine (iPA) (2a) and their corresponding biologically analogous benzyl derivatives have been prepared. Nonnucleophilic acid acceptors have been found to increase the yield of N ^alkylation of adenine nucleosides by 3-methyl-2-butenyl bromide. A76-(3-Methyl-2-butenyl) and A^-benzyl derivatives of adenosine, 2 '-deoxyadenosine, arabinosyladenine, V-0methyladenosine, 3 '-O-methyladenosine, and the corresponding N7-substituted formycins are reported. In addition, N6-benzyl-3 '-deoxyadenosine and the S6-(3-methyl-2-butenyl)substituted 6-mercaptopurine riboside and 6-thioguanosine BIOCHEMISTRY,