title: Synthesis of a Cytokinin Linked by a Spacer to Dexamethasone and Biotin: Conjugates to Detect Cytokinin-Binding Proteins.
abstract: Yeast cells expressing cDNA libraries have provided two new approaches to facilitate further identification of cytokinin-binding proteins and receptors. These are the yeast three hybrid (Y3H) system and fluorescence activated cell sorting (FACS). The Y3H system requires a synthetic hybrid ligand comprising an "anchor" moiety (e.g., dexamethasone) linked to a cytokinin via a spacer. In the yeast nucleus, this ligand by binding connects two fusion proteins leading to a reporter gene activation and detection and characterisation of cytokinin binding proteins. Herein is reported the first synthesis of dexamethasone-cytokinin ligands with a spacer linkage. This was attached to the purine ring of 6-benzylaminopurine (BAP) at positions 2, 8 or 9. To achieve this, dexamethasone was modified by periodate oxidation yielding a carboxylic group used for conjugation to the spacer by amide formation. Biotinyl derivatives of cytokinins for FACS included those synthesised by reaction of an activated ester of biotin with 8-(10-amino-decylamino) derivatives of BAP and BAP 9-riboside. Properties of the conjugates and some biological situations where they could be applicable are discussed briefly.
authors.affiliation: School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia. wyou@uoguelph.ca.
authors.forename: You
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Research School of Biology, Australian National University, Canberra, ACT 0200, Australia. david.letham@bigpond.com.
authors.forename: David S
authors.initials: DS
authors.lastname: Letham
authors.affiliation: Research School of Biology, Australian National University, Canberra, ACT 0200, Australia. peteandjenny.john@gmail.com.
authors.forename: Peter C L
authors.initials: PC
authors.lastname: John
authors.affiliation: School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia. rzhang@uow.edu.au.
authors.forename: Ren
authors.initials: R
authors.lastname: Zhang
mesh_terms: D001593:Benzyl Compounds / Q000737:chemistry / Q000378:metabolism; D001710:Biotin / Q000737:chemistry / Q000378:metabolism*; D003583:Cytokinins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D003907:Dexamethasone / Q000737:chemistry / Q000378:metabolism*; D005434:Flow Cytometry; D017930:Genes, Reporter; D015394:Molecular Structure; D011485:Protein Binding; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D011687:Purines / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: D001593:Benzyl Compounds; D003583:Cytokinins; D011506:Proteins; D011687:Purines; D011993:Recombinant Fusion Proteins; D001710:Biotin; D003907:Dexamethasone; C480551:benzylaminopurine
keywords: 6-benzylaminopurine (BAP); BAP-biotin conjugates; BAP-dexamethasone conjugates; cytokinin-binding proteins; yeast three hybrid