Book of Abstracts: Albany 2009
June 16-20 2009
© Adenine Press (2008)
A Modular Strategy for Tailoring Ribonucleopeptide-based Fluorescent Sensors
A stable complex of a peptide and RNA, ribonucleopeptide (RNP), provides a new framework to construct a macromolecular receptor for small molecules. The RRE RNA and the Rev peptide form a structurally well-characterized stable RNP complex (1) that is suitable for a stepwise functionalization. In vitro selection of the RNP pool originating from an RRE-based RNA library and the Rev peptide affords RNP receptors specific for nucleotide triphosphates (2, 3) or the phosphotyrosine residue.
The RNP receptor functionalized by a fluorophore-labeled Rev peptide exerts optical signals associated with the ligand binding events. Replacing the Rev peptide of the ATP-binding RNP with a fluorophore-modified Rev peptide affords a series of fluorescent ATP sensors (3). This strategy to generate tailor-made fluorescent sensors is applied for a selective detection of a specific phosphorylated tyrosine residue within a defined amino acid sequence (4). The phosphotyrosine-binding RNP receptor and fluorescent RNP sensor constructed from the RNP receptor not only discriminate phosphotyrosine against tyrosine, phosphoserine, or phosphothreonine, but also show specific recognition of amino acid residues surrounding the phosphotyrosine residue. Analyses of the RNA secondary structure of RNP sensors with distinct optical responses revealed a characteristic structural feature at the junction between the RRE segment and the plausible ligand binding region. The RNA structure at the junction is responsible for controlling the emission property of the fluorophore at the N-terminal of the Rev peptide. A strategy for the rational design of fluorescent RNP sensors and structural studies of RNP receptors and sensors will be discussed.
References and Footnotes
Institute of Advanced Energy