Sulfolobus solfataricus beta-glycosidase expressed in Escherichia coli was fully inactivated at 65 degrees C, according to pseudo-first-order kinetics, by [3H]conduritol B epoxide (DL-1,2 anhydro-myo-inositol) synthesized as the active site directed inhibitor by a slight modification of Legler's procedure [Legler, G. (1977) Methods Enzymol. 46, 368-381]. The determination of kinetic constants for the inactivation showed that the process took place through the formation of a stabilized inhibitor-enzyme intermediate. Inactivation and reactivation studies suggested that the inhibitor-enzyme intermediate complex was formed more rapidly and hydrolyzed at a lower rate than it was for other glycosidases. Moreover, the stoichiometry of the binding, determined by electrospray mass spectrometric analysis, revealed that one molecule of the inhibitor was covalently bound to each enzyme subunit. The binding site for [3H]conduritol B epoxide was identified by the isolation and partial sequence analysis of the radioactive peptide obtained by cyanogen bromide and pepsin digests. Electrospray tandem mass analysis of the labeled peptide showed that the inhibitor was covalently bound to E387. This result, in agreement with data obtained from sequence alignments of S. solfataricus beta-glycosidase with other gluco- and galactosidases of the glycosyl hydrolase family 1 [Henrissat, B. (1991) Biochem. J. 280, 309-316], indicates that the conserved E387 is the nucleophilic amino acid residue in the active site of the enzyme.

The base 2-carbon of 2',3'-di-O-acetyl-2'-deoxyinosine is strongly activated towards nucleophillic attack when either the 4-nitrophenyl or 2,4-dinitrophenyl group is attached to its N-1 position (product 1 or 2), 1-(omega-Aminoalkyl)- and 1-(omega-hydroxyalkyl)-2'-deoxyinosine derivatives 5, 8-10 have been efficiently synthesized by a rearrangement of the purine ring upon treatment of compound 1 or 2 with the appropriate alpha,omega-diamine or alpha,omega-hydroxyamine. Moreover 1-amino-2'-deoxyinosine 11 and 1-hydroxy-2'-deoxyinosine 13 have been easily prepared in high yields by reaction of substrate 1 or 2, respectively with hydrazine or hydroxylamine.

6-Chloroxanthosine 1, when activated towards nucleophilic displacement at the 6-C position by conversion into the corresponding 3-N-(2,4-dinitrophenyl) derivative 4, reacted with aq. (NH3)-N-15 to afford [6-N-15]-isoguanosine 3b in 81% overall yield. Catalytic hydrogenation (Pd/C) of 1 led in 60% yield to isoinosine 8; alternatively, this could be obtained in 88% overall yield through alkaline hydrolysis of triphenylphosphonium salt 6, synthesized from 1 by reaction with PPh(3). The reactivity of 1 was further explored by treating it with primary and secondary amines: the 6-N propylamino and the 6-N piperidinyl derivatives (5a and 5b, respectively) could thus both be prepared in more than 90% yield.

An efficient and stereocontrolled solid-phase chemical synthesis of oligosaccarides using a new type of insoluble support (a copolymer of polyethylene glycol and polystyrene) is described. Several Lewis acids were tested as activators of the trichloroacetimidate 12, used as glycosyl donor, in the dimer 13 formation.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of [1-15N]-Labeled 2'-Deoxyinosine and 2'-DeoxyadenosineLorenzo De Napoli, Anna Messere, Daniela Montesarchio, and Gennaro PiccialliCite this: J. Org. Chem. 1995, 60, 7, 2251–2253Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://pubs.acs.org/doi/10.1021/jo00112a053https://doi.org/10.1021/jo00112a053research-articleACS PublicationsRequest reuse permissionsArticle Views231Altmetric-Citations25LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts

The synthesis of thymidine dimers 5a,b containing a chiral carbon in the propionamide internucleosidic linkage is described. These new epimeric dimers were incorporated in oligodeoxyribonucleotides and the melting temperature (Tm) with complementary DNA and RNA as well as the resistence of the single strand against exonuclease were determined.

Isoguanosine 1 was obtained in 76% overall yield starting from 2',3',5'-tri-O-acetylxanthosine 3 in a reaction involving the chloro derivative 4 and the N-(purin-6-yl) pyridinium salt derivative 8 which also proved to be new and valuable synthetic intermediates in the obtainment of C-6-substituted xanthosine derivatives.

Tetrahydro-dUMP, an analog of the putative transition state in aminohydrolysis of deoxycytidine monophosphate (dCMP) inhibits the allosteric enzyme deoxycytidylate aminohydrolase with high affinity. The inhibition is reversible, and its kinetics is consistent with the analog binding at the substrate site only to one and the same conformation that binds the substrate dCMP. Such kinetics is what would be expected for a transition state analog interacting in an allosteric "K system."

2',3'-dideoxy- and 2',3'-dideoxy-2',3'-didehydrocytidine (d2C and d4C) have been synthesized in good yields from 2'-deoxyuridine via dichlorinated derivatives 7a-b. The same synthetic strategy was used in the synthesis of d2C(Me) and d4C(Me) from thymidine. Following this method the evaluable 3'-chloro-2'-deoxycytidine derivatives 9 - 12 can easily be obtained.

N-epsilon-(indole-3-acetyl)-L-Lysine (epsilon-IAA-Lys) and its N-alpha-acetyl derivative (Ac-epsilon-IAA-Lys), products of the metabolism of indole-3-acetic acid (IAA) in Pseudomonas syringae subsp. savastanoi, have been synthesized by a conjugation of IAA with the N-alpha-CBZ-L-lysine p-nitrophenylester. The same synthetic strategy was used to obtain the unnatural conjugate, N-alpha-(indole-3-acetyl)-L-lysine (alpha-IAA-Lys) and its N-epsilon-acetyl derivative (Ac-alpha-IAA-Lys). Comparative bioassay for auxin activity on wheat coleoptiles proved that epsilon-IAA-Lys and Ac-epsilon-IAA-Lys significantly stimulated their growth, although their activity was considerably less than IAA. No activity was shown by alpha-IAA-Lys and Ac-alpha-IAA-Lys.

A convenient solid-phase synthesis of small cyclic oligoribonucleotides based on elongation of the chain by phosphoramidite chemistry, and successive cyclization of the linear fragments by a phosphotriester approach is described.

Cyclic oligodeoxyribonucleotides have been synthesized in satisfactory yields by an easy procedure using polyethylene glycol (PEG) as soluble supporting polymer. The present method is particularly suitable for a medium to large scale synthesis.

The 4-substituted pyrimidine 2′,3′-dideoxy-2′,3′-didehydronucleosides 3 – 10 have been synthesized and the activity of compounds 8 – 10 against HIV evaluated. The synthesis of the 5′-phosphate derivatives 13 – 14 was also reported.

Two new triterpenes, have been isolated from the weed Anagallis arvensis. Their structures, strictly related to that of an oleanane metabolise previously isolated from the same source, have been established on the basis of spectral analyses and chemical correlation with camelliagenin C, a triterpene from Camellia sp.

The synthesis on a polyacrylamide resin of oligonucleotides containing 5,6-dihydroimidazo [1,2-c]pyrimidin-5-one (X) as a base residue is described. Preliminary results on enzymatic hydrolysis of the modified octanucleotide d(TXAATTCA) (21), containing the recognition sequence for the endonuclease ECO RI where dG is replaced by dX (1), are reported.

Reaction of 5'-O-(4,4'-dimethoxytriphenylmethyl)-3'-deoxythy-midine with triphenylphosphine/carbon tetrachloride, followed by deprotection of the 5'-hydroxyl group, afforded the 4-chloro derivative 3 from which some 4-substituted pyrimidin-2(1H)one-2',3'-dideoxyribosides were obtained by nucleophilic substitution under very mild conditions.

Studies on the solid-phase synthesis of cyclic oligonucleotides using CPG or polyacrylamide as a solid matrix are reported. The former support was shown to be not suitable at all since it does not prevent intermolecular couplings. On the other hand, polyacrylamide resin allows the synthesis of medium-size cyclic oligonucleotides provided that the appropriate functionalization of the polymer is used.

The synthesis and the spectral characterization of a number of N4-N4 bridged pyrimidine nucleosides and triazo [4, 3-c] pyrimidine nucleoside analogues are reported.

The cyclic branched oligodeoxyribonucleotides 7 and 8 have been prepared via the intermediate 4 synthesized using a phosphotriester approach.