Book of Abstracts: Albany 2007
June 19-23 2007
Design of Ribonucleopeptide-based Receptors and 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 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 or the phosphotyrosine residue. The phosphotyrosine-binding RNP receptor discriminates phosphotyrosine against tyrosine, phosphoserine, and phosophothreonine.
The ligand-binding surface of RNP is further molded in a stepwise manner by using a Rev peptide library. The Rev peptide appended with seven randomized amino acid residues by means of phage display generates a Rev peptide library. Complex formation of the Rev peptide library with a typical RNA subunit of an ATP-binding RNP affords a peptide-based RNP library. An ATP-binding RNP selected from the peptide-based RNP library shows a higher affinity to ATP and a distinct specificity for ATP over dATP as compared to the original ATP-binding RNP.
The RNP receptor functionalized by a fluorophore-labeled Rev peptide exerts an optical signal associated with the ligand binding events. Replacing the Rev peptide of the ATP-binding RNP with a pyrene-modified Rev peptide affords a fluorescent ATP sensor. Strategies to functionalize the RNP receptors will be discussed.
Institute of Advanced Energy