7-Iodo-5-aza-7-deazaguanine ribonucleoside: crystal structure, physical properties, base-pair stability and functionalization.
Acta Crystallogr C Struct Chem
; 76(Pt 5): 513-523, 2020 05 01.
Article
em En
| MEDLINE
| ID: mdl-32367834
ABSTRACT
The positional change of nitrogen-7 of the RNA constituent guanosine to the bridgehead position-5 leads to the base-modified nucleoside 5-aza-7-deazaguanosine. Contrary to guanosine, this molecule cannot form Hoogsteen base pairs and the Watson-Crick proton donor site N3-H becomes a proton-acceptor site. This causes changes in nucleobase recognition in nucleic acids and has been used to construct stable `all-purine' DNA and DNA with silver-mediated base pairs. The present work reports the single-crystal X-ray structure of 7-iodo-5-aza-7-deazaguanosine, C10H12IN5O5 (1). The iodinated nucleoside shows an anti conformation at the glycosylic bond and an N conformation (O4'-endo) for the ribose moiety, with an antiperiplanar orientation of the 5'-hydroxy group. Crystal packing is controlled by interactions between nucleobase and sugar moieties. The 7-iodo substituent forms a contact to oxygen-2' of the ribose moiety. Self-pairing of the nucleobases does not take place. A Hirshfeld surface analysis of 1 highlights the contacts of the nucleobase and sugar moiety (O-H...O and N-H...O). The concept of pK-value differences to evaluate base-pair stability was applied to purine-purine base pairing and stable base pairs were predicted for the construction of `all-purine' RNA. Furthermore, the 7-iodo substituent of 1 was functionalized with benzofuran to detect motional constraints by fluorescence spectroscopy.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Temas:
Agentes_cancerigenos
Base de dados:
MEDLINE
Assunto principal:
Purinas
/
Ribonucleosídeos
/
Prata
/
DNA
/
Ácidos Nucleicos
/
Guanosina
Idioma:
En
Revista:
Acta Crystallogr C Struct Chem
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Alemanha