Modified guanosine monophosphates have been employed to introduce various functional groups onto RNA 5'-ends. Applications of modified RNA 5'-ends include the generation of functionalized RNA libraries for in vitro selection of catalytic RNAs, the attachment of photoaffinity-tags for mapping RNA-protein interactions or active sites in catalytic RNAs, or the non-radioactive labeling of RNA molecules with fluorescent groups. While in these and in similar applications a stable linkage is desired, in selection experiments for generating novel catalytic RNAs it is often advantageous that a functional group is introduced reversibly. Here we give a quantitative comparison of the different strategies that can be applied to reversibly attach functional groups via disulfide bonds to RNA 5'-ends. We report the preparation of functional groups with disulfide linkages, their incorporation efficiency into an RNA library, and their stability under various conditions. Copyright (C) 2000 Elsevier Science Ltd.
Bibliographical noteFunding Information:
This study was supported by grants of the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie to M.F. and by a NATO travel grant to M. F. and J. S. N. We thank Nicole Rubner for operating HPLC-stability studies, Carol Zehetmeier for excellent technical assistance, Michael Blind, Günter Mayer, Felix Hausch, Barbara Gatto, Nikolai Raffler and Oliver Thum for helpful discussions and Wolfgang Steglich and Ernst-L. Winnacker for support. A. J. and B. S. express their gratitude to the DFG for support. J. S. N. thanks the following agencies for support in the form of awards: the Camille and Henry Dreyfus Foundation (Teacher-Scholar Award), the Alfred P. Sloan Foundation (Alfred P. Sloan Research Fellowship), and the American Chemical Society (Arthur C. Cope Scholar Award).