title: Synthesis and crystallographic analysis of 5-Se-thymidine DNAs.
abstract: We investigated the possibility of the interaction of 5-CH(3) of thymidine and its 5'-phosphate backbone (C-H...O(-)-PO(3) interaction) in DNA via the insertion of the atomic probe (a selenium atom) into the exo-5-position of thymidine (5-Se-T). 5-Se-T was synthesized for the first time, via Mn(OAc)(3) assisted electrophilic addition of CH(3)SeSeCH(3) to 3',5'-di-O-benzoyl-2'-deoxyuridine. The 5-Se-T phosphoramidite was subsequently synthesized and incorporated into DNA in over 99% coupling yield. Biophysical and structural investigations of the 5-Se-T DNAs revealed that the Se-modified and nonmodified DNAs are virtually identical. In addition, the crystallographic analysis of a 5-Se-T DNA strongly suggests a hydrogen-bond formation between the 5-CH(3) and 5'-phosphate groups (CH(3)...PO(4)(-) interaction).
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, USA.
authors.forename: Abdalla E A
authors.initials: AE
authors.lastname: Hassan
authors.forename: Jia
authors.initials: J
authors.lastname: Sheng
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Jiang
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
mesh_terms: D001483:Base Sequence; D018360:Crystallography, X-Ray / Q000379:methods; D004247:DNA / Q000138:chemical synthesis* / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000138:chemical synthesis / Q000737:chemistry; D016566:Organoselenium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012643:Selenium / Q000032:analysis* / Q000737:chemistry; D013936:Thymidine / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D009841:Oligonucleotides; D009943:Organophosphorus Compounds; D016566:Organoselenium Compounds; D004247:DNA; D012643:Selenium; D013936:Thymidine