A DFDL UV picosecond fluorescence spectrometer: Application to aqueous solutions of peptides and nucleotide dye conjugates
摘要:
AbstractUsing a new type of fluorescence lifetime spectrometer, the time resolution of single shot fluorescence detection is improved by two orders of magnitude. The spectrometer is based on a streak camera and an excimer laser pumped distributed feedback dye laser (DFDL) providing UV pulses of 50 μJ and 15 ps FWHM, corresponding to a peak power of ∼ 5 · 106 W in the ultraviolet. —This spectrometer is used to investigate the fluorescence decay of peptides containing a tyrosine as the single fluorophore. Peptides with tyrosine at the N‐terminus reveal a biexponential decay, while peptides with C‐terminal tyrosine are mainly monoexponential. This difference can be explained by the relative orientation of the fluorescing phenol ring and the quenching peptide bond. —The fluorescence decay of a number of peptides with tyrosine in a non terminal position can be described by two lifetimes, 2.3 · 0.1 ns and 380 ± 70 ps, where the percentage of the long lifetime increases to up to 100% when the rotational flexibility of the peptide chain decreases, either due to increasing weight of the chain or due to formation of an H‐bridge. —Similar processes seem to be relevant for the fluorescence of the dye coumarin 120 coupled to nucleotides. The fluorescence lifetime of such molecules is significantly different, so that the four DNA nucleotides can be identified on the basis of the fluorescence decay of the attached dye.
Towards mRNA with superior translational activity: synthesis and properties of ARCA tetraphosphates with single phosphorothioate modifications
作者:Malwina Strenkowska、Joanna Kowalska、Maciej Lukaszewicz、Joanna Zuberek、Wei Su、Robert E. Rhoads、Edward Darzynkiewicz、Jacek Jemielity
DOI:10.1039/b9nj00644c
日期:——
We describe the chemical synthesis and preliminary biophysical and biochemical characterization of a series of mRNA 5' end (cap) analogs designed as reagents for obtaining mRNA molecules with augmented translation efficiency and stability in vivo and as useful tools to study mRNA metabolism. The analogs share three structural features: (i) 5',5'- bridge elongated to tetraphosphate to increase their
Systematic evolution of ligands by exponential enrichment: Chemi-ESLEX
申请人:——
公开号:US20030186231A1
公开(公告)日:2003-10-02
This application provides methods for identifying nucleic acid ligands capable of covalently interacting with targets of interest. The nucleic acids can be associated with various functional units. The method also allows for the identification of nucleic acids that have facilitating activities as measured by their ability to facilitate formation of a covalent bond between the nucleic acid, including its associated functional unit, and its target.
Methods and reagents for introducing a sulfhydryl group into the 5'-terminus of RNA
申请人:——
公开号:US20030165849A1
公开(公告)日:2003-09-04
Methods for synthesizing RNA molecules whose 5′-terminus comprises a thiol group are disclosed. The present invention discloses the formation of 5′-HS-PEG-GMP-RNA and 5′-GMPS-RNA which upon alkaline phosphatase treatment, independently lead to a 5′-HS-RNA molecule.
Amino acids present in domains of an umami taste receptor are described herein, wherein the amino acids interact with at least one nucleotide derivative and/or at least one transmembrane compound that potentiates, modulates, increases, and/or enhances the activity of the umami receptor. Such compounds can be used in flavor compositions to enhance the umami taste and/or palatability of food products.
The present invention provides a method of assaying an enzyme-mediated coupling reaction between a first and a second reactant. The method comprises contacting the first reactant with the second reactant in the presence of the enzyme. The second reactant comprises a thiol derivative to yield a first product comprising a thiol derivative. The thiol derivative is then detected in the first product.