title: Bis-triazolyl diguanosine derivatives as synthetic transmembrane ion channels.
abstract: In nature, ion channels facilitate the transport of ions across biological membranes. The development of artificial ion channels that can mimic the fundamental functions of the natural ones would be of great importance to biological research. Artificial ion channels based on nucleoside derivatives are expected to be biocompatible with functions that can be controlled by the presence or absence of biologically relevant molecules. This protocol describes the detailed procedures for the synthesis and ion-channel activity of four diguanosine derivatives, each made up of two guanosine moieties separated by a covalent linker (e.g., PEG). The procedure describes the preparation of guanosine azide and guanosine alkine building blocks, as well as the preparation of four distinct synthetic linkers each containing either two alkynes or two azides. The diguanosine derivatives are synthesized using a 'one-pot' modular synthetic approach based on Cu(I)-catalyzed azide and alkyne cycloaddition. The ion-channel activity of these diguanosine derivatives for the transportation of ions across a phospholipid bilayer is investigated using voltage-clamp experiment. By using the PEG-containing diguanosine as an example, we describe how to determine the ion-channel activity in the presence of different metal ions (e.g., Na(+), K(+) and Cs(+)) and the inhibition of the ion-channel activity using the nucleobase cytosine. The approximate time frame for the synthesis of the PEG dinucleoside is 3 d, and that for the experiments to evaluate its ability to transport K(+) ion across a phospholipid bilayer is ∼8-10 h.
authors.affiliation: Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, India.
authors.forename: Y Pavan
authors.initials: YP
authors.lastname: Kumar
authors.affiliation: Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, India.|Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
authors.forename: Rabindra Nath
authors.initials: RN
authors.lastname: Das
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: Ole Mathis
authors.initials: OM
authors.lastname: Schütte
authors.affiliation: Institute of Organic and Biomolecular Chemistry, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Steinem
authors.affiliation: Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, India.|Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
authors.forename: Jyotirmayee
authors.initials: J
authors.lastname: Dash
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry*; D002462:Cell Membrane / Q000378:metabolism*; D006151:Guanosine / Q000737:chemistry*; D007473:Ion Channels / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D014230:Triazoles / Q000737:chemistry*
chemical_list: D007473:Ion Channels; D014230:Triazoles; D006151:Guanosine