title: Synthesis of a 4-selenothymidine phosphoramidite and incorporation into oligonucleotides.
abstract: The detailed synthetic protocol for a 4-selenothymidine phosphoramidite and its use to prepare modified oligonucleotides is described here. The Se-phosphoramidite synthesis was achieved by developing a useful protection and deprotection system for the selenium functionality. The coupling reaction of the Se-phosphoramidite during solid-phase oligonucleotide synthesis is quantitative, and the oligonucleotides containing the Se-modification are stable. Based on crystal structure analysis, the selenium-modified oligonucleotides retain base-pairing like their native counterparts, and the derivatized DNA structure is virtually identical to the native structure. This achievement will present a novel opportunity for structural studies of nucleic acids and their protein complexes, because selenium can resolve the phase problem in macromolecular X-ray crystallography. In addition, this atom-specific replacement of oxygen with selenium will provide a useful tool for investigating biochemical and biophysical properties of nucleic acids and their protein complexes.
authors.affiliation: Georgia State University, Atlanta, Georgia, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Sheng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D010756:Phosphoric Acids / Q000138:chemical synthesis* / Q000737:chemistry; D012643:Selenium / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013936:Thymidine / Q000737:chemistry*
chemical_list: D000577:Amides; D009841:Oligonucleotides; D010756:Phosphoric Acids; C011067:phosphoramidic acid; D012643:Selenium; D013936:Thymidine