title: Efficient access to 3'-terminal azide-modified RNA for inverse click-labeling patterns.
abstract: Labeled RNA becomes increasingly important for molecular diagnostics and biophysical studies on RNA with its diverse interaction partners, which range from small metabolites to large macromolecular assemblies, such as the ribosome. Here, we introduce a fast synthesis path to 3'-terminal 2'-O-(2-azidoethyl) modified oligoribonucleotides for subsequent bioconjugation, as exemplified by fluorescent labeling via Click chemistry for an siRNA targeting the brain acid-soluble protein 1 gene (BASP1). Importantly, the functional group pattern is inverse to commonly encountered alkyne-functionalized "click"-able RNA and offers increased flexibility with respect to multiple and stepwise labeling of the same RNA molecule. Additionally, our route opens up a minimal step synthesis of 2'-O-(2-aminoethyl) modified pyrimidine nucleoside phosphoramidites which are of widespread use to generate amino-modified RNA for N-hydroxysuccinimide (NHS) ester-based conjugations.
authors.affiliation: Institute of Organic Chemistry and ‡Institute of Biochemistry, Center for Molecular Biosciences CMBI, University of Innsbruck , 6020 Innsbruck, Austria.
authors.forename: Tobias
authors.initials: T
authors.lastname: Santner
authors.forename: Markus
authors.initials: M
authors.lastname: Hartl
authors.forename: Klaus
authors.initials: K
authors.lastname: Bister
authors.forename: Ronald
authors.initials: R
authors.lastname: Micura
mesh_terms: D000818:Animals; D001386:Azides / Q000737:chemistry*; D002460:Cell Line; D002645:Chickens; D057930:Click Chemistry; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000235:genetics; D005453:Fluorescence; D008856:Microscopy, Fluorescence; D015394:Molecular Structure; D009843:Oligoribonucleotides / Q000737:chemistry*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D034741:RNA, Small Interfering / Q000737:chemistry*
chemical_list: D001386:Azides; D003598:Cytoskeletal Proteins; D009843:Oligoribonucleotides; D012333:RNA, Messenger; D034741:RNA, Small Interfering