TheHigh-Anti Conformation of 7-Halogenated 8-Aza-7-deaza-2′-deoxy-guanosines: A Study of the Influence of Modified Bases on the Sugar Structure of Nucleosides

Seela, Frank; Rosemeyer, H.; Reuter, Hans; Kastner, Guido; Mikhailopulo, Igor A.

doi:10.1002/(sici)1522-2675(19990113)82:1<105::aid-hlca105>3.0.co;2-3

Cited by 34 publications

(26 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…± To investigate the discrimination of the iodo nucleoside 2c towards the four canonical DNA constituents, hybridization experiments were performed according to Table 7. As expected, the base pair 2c´dT is the strongest (112 1, T m 578), while those of the duplexes forming mismatches melt at a significantly 5'-d( TAG G3cC AA3c ACT )-3' (28) 50 À 90.58 À 254.11 À 11.77 3'-d( ATC C2aG TT2a TGA )-5' (14) lower temperature ( Table 7). The discrimination of the iodo nucleoside 2c is similar to that of the canonical nucleosides, except that the duplex 33´21 (T m 508) shows a 78 lower T m value than the duplex 11´21 (T m 578), while duplex 33´12 (T m 468) has almost the same stability as the parent duplex 11´12 (T m 488).…”

Section: 2mentioning

confidence: 77%

“…According to Table 1, the 8-aza-7-deazapurin-2,6-diamine nucleoside 2a shows a higher N-conformer population than the corresponding purine nucleoside 1. The conformation around the C(4')ÀC(5') bond indicates that the 8-aza-7-deazapurine-2,6-diamine nucleoside 2c, as the 8-aza-7-deaza-2'-deoxyguanosines [14], prefers the g t -(À sc)-rotamer population, while, for the regular purine nucleosides, the g g -( sc)-or the g gÀ -(ap) conformation is predominant [15]. The conformation of the sugar moieties of the pyrimidine nucleosides 3a ± c is also influenced by the substitution at the 5-position ( Table 1).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Major-Groove-Halogenated DNA: The Effects of Bromo and Iodo Substituents Replacing H−C(7) of 8-Aza-7-deazapurine-2,6-diamine or H−C(5) of Uracil Residues

Seela

2001

HCA

Self Cite

View full text Add to dashboard Cite

Oligonucleotides containing halogenated purine and pyrimidine bases were synthesized. Bromo and iodo substituents were introduced at the 7-position of 8-aza-7-deazapurine-2,6-diamine (see 2b,c) or at the 5-position of uracil residues (see 3b,c). Phosphoramidites were synthesized after protection of 2b with the isobutyryl residue and of 2c with the benzoyl group. Duplexes containing the residues 2b or 2c gave always higher T m values than those of the nonmodified counterparts containing 2'-deoxyadenosine, the purine-2,6-diamine 2'-deoxyribonucleoside (1), or 2a at the same positions. Six 2b residues replacing dA in the duplex 5'-d(TAGGTCAATACT)-3' (11)´5'-d(AGTATTGACCTA)-3' (12) raised the T m value from 48 to 758 (4.58 per modification ( Table 3)). Contrary to this, incorporation of the 5-halogenated 2'-deoxyuridines 3b or 3c into oligonucleotide duplexes showed very little influence on the thermal stability, regardless of which purine nucleoside was located opposite to them (Tables 4 and 5). The positive effects on the thermal stability of duplexes observed in DNA were also found in DNA´RNA hybrids or in DNA with parallel chain orientation (Tables 8 and 9, resp.).Introduction. ± The thermal stability of oligonucleotide duplexes increases when 7-substituted 8-aza-7-deazapurines ( pyrazolo[3,4-d]pyrimidines) replace purines [1] [2]. This effect is particularly strong when the heterocyclic base is an 8-aza-7-deazaguanine and carries a halogeno substituent at the 7-position [1] [3] [4]. Recent studies on the substitution of purine-2,6-diamine by the 7-bromo derivative of 8-aza-7-deazapurine-2,6-diamine have shown that this modified purine derivative forms as stable base a pair with thymine as guanine does with cytosine [5]. In contrast, the base pair of the structurally related purine-2,6-diamine 2'-deoxyribonucleoside (1; n 2 A d ) with thymidine is rather weak when introduced into duplex DNA [5] [6].

show abstract

Section: 2mentioning

confidence: 77%

mentioning

confidence: 99%

Major-Groove-Halogenated DNA: The Effects of Bromo and Iodo Substituents Replacing H−C(7) of 8-Aza-7-deazapurine-2,6-diamine or H−C(5) of Uracil Residues

Seela

2001

HCA

Self Cite

View full text Add to dashboard Cite

show abstract

“…Calculated Pseudorotational Parameters and the Rotational Equilibrium about the C(4')ÀC(5') Bond of the 8-Aza-7-deazaadenine 2'-deoxyribonucleosides 1a ± c and 2a ± c a ) [22]. Single-crystal X-ray analyses show that the regularly linked pyrazolo[3,4-d]-pyrimidine nucleosides of type 1 show a rather different N-glycosylic-bond conformation (high-anti) compared to the purine nucleosides [23]; these changes are also observed in the CD spectra [23]. Fig.…”

mentioning

confidence: 99%

Base-Pairing Properties of 8-Aza-7-deazaadenine Linked via the 8-Position to the DNA Backbone

Seela

Zulauf

Debelak

2000

HCA

Self Cite

View full text Add to dashboard Cite

The base-pairing properties of oligonucleotides containing the unusual N 8 -linked 8-aza-7-deazaadenine 2'-deoxyribonucleoside (2a) as well as its 7-bromo derivative 2b are described. The oligonucleotides were prepared by solid-phase synthesis employing phosphoramidite chemistry. Compound 2a forms a strong base pair with T d for which a reverse Watson-Crick pair is suggested (Fig. 9). Compound 2a displays a lower N-glycosylic-bond stability than its N 9 -nucleoside and shows strong stacking interactions when incorporated into oligonucleotides. The replacement of 2'-deoxyadenosine by 2a does not significantly influence the duplex stability. However, this behavior depends on the position of the incorporation.

show abstract

“…According to Table 2 8-aza-7-deazapurin-2,6-diamine nucleosides 2a,b show a more pronounced N conformer population than the corresponding purine nucleoside 1, while the N-type population of the related 7-deazapurine nucleoside 3 is decreased. The conformation around the C(4′)-C(5′) bond indicates that 8-aza-7-deazapurin-2,6-diamine nucleosides 2a,b, as for 8-aza-7-deaza-2′-deoxyguanosines (25), prefer the γ t -(-sc) rotamer population, while for the regular purine nucleosides the γ (+)g -(+sc) conformation is predominant (26). This means that in both cases the nucleobase and the CH 2 OH group undergo a disrotatory motion so that the Coulomb repulsion between N(8) and O(5′) and O(4′) is minimized.…”

Section: Monomersmentioning

confidence: 99%

“…2B) adopt the A-DNA form. Nevertheless, purin-2,6-diamine nucleoside 1 as well as the 8-aza-7-deazapurine derivatives 2a,b induce spectral changes which are the result of conformational differences between purine and 8-aza-7-deazapurine nucleosides (25).…”

Section: Oligonucleotidesmentioning

confidence: 99%

Pyrazolo[3,4-d]pyrimidine Nucleic Acids: Adjustment of the dA-dT to the dG-dC Base Pair Stability

Budow

Seela

2003

Nucleosides, Nucleotides and Nucleic Acids

View full text Add to dashboard Cite

TheHigh-Anti Conformation of 7-Halogenated 8-Aza-7-deaza-2′-deoxy-guanosines: A Study of the Influence of Modified Bases on the Sugar Structure of Nucleosides

Cited by 34 publications

References 23 publications

Major-Groove-Halogenated DNA: The Effects of Bromo and Iodo Substituents Replacing H−C(7) of 8-Aza-7-deazapurine-2,6-diamine or H−C(5) of Uracil Residues

Major-Groove-Halogenated DNA: The Effects of Bromo and Iodo Substituents Replacing H−C(7) of 8-Aza-7-deazapurine-2,6-diamine or H−C(5) of Uracil Residues

Base-Pairing Properties of 8-Aza-7-deazaadenine Linked via the 8-Position to the DNA Backbone

Pyrazolo[3,4-d]pyrimidine Nucleic Acids: Adjustment of the dA-dT to the dG-dC Base Pair Stability

Contact Info

Product

Resources

About