A photo-sensitive ribonucleotide of 5-iodo-2-oxo(1H) pyridine (Iy) capable of site-specific incorporation into transcripts was developed. The site-specific Iy incorporation into RNA was achieved by T7 transcription mediated by unnatural base pairing between Iy and its partner, 2-amino-6-(2-thienyl)purine (s). By this specific transcription, Iy was incorporated into an anti(Raf-1) RNA aptamer, which binds to human Raf-1 and inhibits the interaction between Raf-1 and Ras. Protein-dependent photo-dimerization of the aptamer was observed when Iy was located at specific positions in the aptamer, showing that the site-specific incorporation of the photo-sensitive component into RNA achieves highly specific crosslinking. This specific transcription mediated by the unnatural base pair would be a powerful tool for generating high-affinity RNA ligands and for analyzing RNA-RNA and RNA-protein interactions, as well as for constructing RNA-based nanostructures.
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http://dx.doi.org/10.1016/j.chembiol.2003.12.016 | DOI Listing |
Materials (Basel)
December 2024
Istituto Universitario di Studi Superiori IUSS-Department STS, Scuola Universitaria Superiore Pavia, 27100 Pavia, Italy.
This study evaluates the API 650 design procedure for steel storage tanks, incorporating nonlinear dynamic analysis with large deformation effects. Focusing on seismic vulnerability, the case study examines storage tanks proposed for construction in Naples, Italy, assessing their performance under site-specific seismic conditions. A target spectrum and 20 earthquake records were selected to reflect regional seismic characteristics.
View Article and Find Full Text PDFACS Sens
January 2025
Materials Interfaces Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, P. R. China.
Over recent years, the LUMinescent AntiBody Sensor (LUMABS) system, utilizing bioluminescence resonance energy transfer (BRET), has emerged as a highly effective method for antibody detection. This system incorporates NanoLuc (Nluc) as the donor and fluorescent protein (FP) as the acceptor. However, the limited Stokes shift of FP poses a challenge, as it leads to significant spectral cross-talk between the excitation and emission spectra.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA.
Ancestral sequence reconstruction (ASR) is typically performed using homogeneous evolutionary models, which assume that the same substitution propensities affect all sites and lineages. These assumptions are routinely violated: heterogeneous structural and functional constraints favor different amino acid states at different sites, and these constraints often change among lineages as epistatic substitutions accrue at other sites. To evaluate how realistic violations of the homogeneity assumption affect ASR, we developed site-specific substitution models and parameterized them using data from deep mutational scanning experiments on three protein families; we then used these models to perform ASR on the empirical alignments and on alignments simulated under heterogeneous conditions derived from the experiments.
View Article and Find Full Text PDFApplications of genetic code expansion in live cells are widespread and continually emerging, yet they have been limited by their reliance on the supplementation of non-standard amino acids (nsAAs) to cell culturing media. While advances in cell-free biocatalysis are improving nsAA synthesis cost and sustainability, such processes remain reliant on multi-step processes of product isolation followed by supplementation to engineered cells. Here, we report the design of a modular and genetically encoded system that combines the steps of biosynthesis of diverse phenylalanine derivatives, which are the most frequently used family of nsAAs for genetic code expansion, and their site-specific incorporation within target proteins using a single engineered bacterial host.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry - Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden.
Isonitrile-derivatized amino acids are emerging as highly effective infrared (IR) probes for investigating the structures and dynamics of hydrogen (H)-bonds. These probes enable the quantification of chemical exchange processes in solute-solvent complexes via two-dimensional IR spectroscopy and hold significant promise for site-specific dynamic studies within proteins. Despite their potential, theoretical models that elucidate the solvatochromism of isonitriles remain underdeveloped.
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