Solid-phase synthesis of oligomeric deoxynucleic guanidine (DNG): A polycationic analogue of DNA

Linkletter, Barry A.; Bruice, Thomas C.

doi:10.1016/s0960-894x(98)00228-5

Cited by 19 publications

(16 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Except for the 2Ј-fluoro-N3Ј-P5Ј-phosphoramidates, these analogues are neutral and thus eliminate the electrostatic repulsion of negative charges present in natural DNA and RNA. An alternative approach, involves replacement of anionic phosphodiester groups by cationic linkages (13)(14)(15)(16)(17) or the use of oligonucleotides conjugated with positively charged groups to provide zwitterionic DNA analogues (18)(19)(20). These ODNs show increased binding with complementary DNA or RNA.…”

mentioning

confidence: 99%

“…Our ongoing research in this area is focused on the development of deoxynucleic guanidine (DNG) in which the negatively charged OOO(PO 2 Ϫ )OOO backbone of DNA is replaced by positively charged, achiral ONHOC(ANH 2 ϩ )ONH O linkage (15)(16)(17) to provide very stable complexes (21,22). As DNG is positively charged, it binds effectively to target DNA or RNA because the repulsive electrostatic effects in double-stranded DNA (dsDNA) would be replaced by attractive electrostatic interactions in DNG:DNA or DNG:RNA duplexes.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, biophysical properties, and nuclease resistance properties of mixed backbone oligodeoxynucleotides containing cationic internucleoside guanidinium linkages: Deoxynucleic guanidine/DNA chimeras

Barawkar

Bruice

1998

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The synthesis of mixed backbone oligodeoxynucleotides (18-mers) consisting of positively charged guanidinium linkages along with negatively charged phosphodiester linkages is carried out. The use of a base labileprotecting group for guanidinium linkage offers a synthetic strategy similar to standard oligonucleotide synthesis. The nuclease resistance of the oligodeoxyribonucleotides capped with guanidinium linkages at 5 and 3 ends are reported. The hybridization properties and sequence specificity of binding of these deoxynucleic guanidine͞DNA chimeras with complementary DNA or RNA are described.The use of antisense oligodeoxyribonucleotides (ODNs) to regulate gene products requires the development of modified ODNs possessing the properties of enhanced cellular uptake, nuclease resistance, and sequence specific hybridization to complementary RNAs. Numerous DNA structural analogues with modified heterocycle, sugar, and phosphodiester backbone moieties have been synthesized (1-3). Substantial progress has been made toward successful backbone modifications by using phosphorus and non-phosphorus groups (4, 5). A number of modifications or replacements of phosphodiester linkages such as 2Ј-fluoro-N-3Ј-P5Ј-phosphoramidates (6), 3Ј-thioformacetals (7, 8), 2Ј-O-Me methylene(methylimino) (9), 2Ј-O-Me amide (10), 2Ј-O-methylribonucleoside methylphosphonate (11), and peptide nucleic acid (PNA) (12) have been shown to complement with DNA and RNA with similar or higher stability while maintaining the sequence specificity. Except for the 2Ј-fluoro-N3Ј-P5Ј-phosphoramidates, these analogues are neutral and thus eliminate the electrostatic repulsion of negative charges present in natural DNA and RNA. An alternative approach, involves replacement of anionic phosphodiester groups by cationic linkages (13-17) or the use of oligonucleotides conjugated with positively charged groups to provide zwitterionic DNA analogues (18)(19)(20). These ODNs show increased binding with complementary DNA or RNA. Conceptually, replacement of anionic phosphodiester linkage by neutral or positively charged linkages can modulate the net charge of antisense ODN complex and thereby may enhance its antisense properties (4).Our ongoing research in this area is focused on the development of deoxynucleic guanidine (DNG) in which the negatively charged OOO(PO 2 Ϫ )OOO backbone of DNA is replaced by positively charged, achiral ONHOC(ANH 2 ϩ )ONH O linkage (15-17) to provide very stable complexes (21, 22). As DNG is positively charged, it binds effectively to target DNA or RNA because the repulsive electrostatic effects in double-stranded DNA (dsDNA) would be replaced by attractive electrostatic interactions in DNG:DNA or DNG:RNA duplexes. On the other hand, if electrostatic binding between polycationic and polyanionic structures becomes more significant than the specific interactions between heterocyclic bases, then binding becomes nonspecific and independent of complementary base pairing. To overcome this possible limitation, we propose to synthesize m...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis, biophysical properties, and nuclease resistance properties of mixed backbone oligodeoxynucleotides containing cationic internucleoside guanidinium linkages: Deoxynucleic guanidine/DNA chimeras

Barawkar

Bruice

1998

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Subsequently, two different approaches for the solid phase-supported synthesis of DNG oligomers were introduced. They enabled chain elongation either in the 5'→3' [ 52 ] or 3'→5' [ 53 ] direction, respectively. Starting from protected 3',5'-dideoxy-5'-amino-3'-azidothymidine 21 , the 5'→3' route was based on the synthesis of the diamino intermediate 22 and thiourea monomer 23 , which was then converted into a reactive carbodiimide 24 and coupled to a terminal amino group of the solid phase 25 ( Scheme 2 ).…”

Section: Reviewmentioning

confidence: 99%

Oligonucleotide analogues with cationic backbone linkages

Meng¹,

Ducho²

2018

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

Their unique ability to selectively bind specific nucleic acid sequences makes oligonucleotides promising bioactive agents. However, modifications of the nucleic acid structure are an essential prerequisite for their application in vivo or even in cellulo. The oligoanionic backbone structure of oligonucleotides mainly hampers their ability to penetrate biological barriers such as cellular membranes. Hence, particular attention has been given to structural modifications of oligonucleotides which reduce their overall number of negative charges. One such approach is the site-specific replacement of the negatively charged phosphate diester linkage with alternative structural motifs which are positively charged at physiological pH, thus resulting in zwitterionic or even oligocationic backbone structures. This review provides a general overview of this concept and summarizes research on four according artificial backbone linkages: aminoalkylated phosphoramidates (and related systems), guanidinium groups, S-methylthiourea motifs, and nucleosyl amino acid (NAA)-derived modifications. The synthesis and properties of the corresponding oligonucleotide analogues are described.

show abstract

“…To be an effective antisense or antigene agent, DNG must be available in longer sequences that can recognize unique sites in the human genome. A solid-phase synthetic method was developed to make longer oligomers . The single most important feature of solid-phase synthesis is that purification after each synthetic cycle is accomplished by washing the solid support to which the growing oligomer is covalently attached.…”

Section: Introductionmentioning

confidence: 99%

Solid-Phase Synthesis of Deoxynucleic Guanidine (DNG) Oligomers and Melting Point and Circular Dichroism Analysis of Binding Fidelity of Octameric Thymidyl Oligomers with DNA Oligomers

1999

Self Cite

View full text Add to dashboard Cite

A practical solid-phase synthesis of deoxynucleic guanidine (DNG), a positively charged DNA backbone analogue, is reported. The nucleoside coupling step in the solid-phase synthesis of DNG involves the attack of a terminal 3′-amine upon an electronically activated 5′-carbodiimide to create a protected guanidinium internucleoside linkage. The activated carbodiimide is synthesized in situ by the mercury(II) abstraction of sulfur from an unsymmetrically substituted thiourea in which one substituent is an electronwithdrawing protecting group and the other is the 5′-nucleoside monomer. This produces, in addition to the carbodiimide, a mercury sulfide precipitate which accumulates in the pores of the solid support, restricting solvent and reagent access and reducing the coupling yields with each successive cycle. This obstacle is overcome by a simple washing step involving a thiophenol solution which readily removes the mercury salt. The addition of this step to the cycle enables DNG oligomers to be synthesized using standard macroporous SPS supports. Coupling yields of 98% were estimated from the HPLC analysis of the product mixtures. An octameric thymidyl oligomer (II) was synthesized and the fidelity of binding to octameric adenyl DNA oligomers containing cytidyl mismatches was determined. Binding was studied by thermal denaturation (Tm), Job plots, and circular dichroism spectrophotometry. The DNG oligomer (II) formed a 2:1 complex with octameric adenyl DNA (III) with a melting temperature of 63°C. Each cytidyl mismatch induced a penalty of 4 to 5°C in the observed melting temperatures. DNA sequences with four or more mismatches showed no base pairing in the presence of II. No association was observed between II and octameric cytidyl DNA. These observations demonstrate that DNG oligomers of moderate length are able to discriminate between complementary and mismatched DNA oligomers.

show abstract

Solid-phase synthesis of oligomeric deoxynucleic guanidine (DNG): A polycationic analogue of DNA

Cited by 19 publications

References 19 publications

Synthesis, biophysical properties, and nuclease resistance properties of mixed backbone oligodeoxynucleotides containing cationic internucleoside guanidinium linkages: Deoxynucleic guanidine/DNA chimeras

Synthesis, biophysical properties, and nuclease resistance properties of mixed backbone oligodeoxynucleotides containing cationic internucleoside guanidinium linkages: Deoxynucleic guanidine/DNA chimeras

Oligonucleotide analogues with cationic backbone linkages

Solid-Phase Synthesis of Deoxynucleic Guanidine (DNG) Oligomers and Melting Point and Circular Dichroism Analysis of Binding Fidelity of Octameric Thymidyl Oligomers with DNA Oligomers

Contact Info

Product

Resources

About