Raman and FTIR spectroscopy have been used to characterize the structure of 5'untranslated region (5'UTR, 342-mer RNA) of the HCV genome. The study of the 750-850 cm(-1) Raman spectral domain of the ribose-phosphate backbone reveals that the percentage of nucleobases involved in double helix-loop junctions is 19+/-1%, which is very close to that of a theoretical secondary structure model (18.7%) proposed on the basis of comparative sequence analysis and thermodynamic modelling. In addition, about 68+/-2% of the bases are helically ordered having C(3')-endo ribofuranose pucker. FTIR-monitored H/D exchange provides the following results: (a) base-paired guanine and cytosine nucleobases show the lowest rate of isotopic exchange, and some synchronous intensity changes of marker bands of A.U pair and single stranded adenine are consistent with the presence of A(*)A.U triplets; (b) the vibrational coupling between the ribose ether C-O stretching and 2'OH bending motions reveals that helical regions of 5'UTR RNA are characterized by hydrogen bonding between the 2'OH ribose groups and the ether oxygen atoms of neighbouring ribose residues.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.bpc.2006.06.010 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616.
Seeds are complex structures composed of three regions, embryo, endosperm, and seed coat, with each further divided into subregions that consist of tissues, cell layers, and cell types. Although the seed is well characterized anatomically, much less is known about the genetic circuitry that dictates its spatial complexity. To address this issue, we profiled mRNAs from anatomically distinct seed subregions at several developmental stages.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138.
C-Terminal cyclic imides are posttranslational modifications that can arise from spontaneous intramolecular cleavage of asparagine or glutamine residues resulting in a form of irreversible protein damage. These protein damage events are recognized and removed by the E3 ligase substrate adapter cereblon (CRBN), indicating that these aging-related modifications may require cellular quality control mechanisms to prevent deleterious effects. However, the factors that determine protein or peptide susceptibility to C-terminal cyclic imide formation or their effect on protein stability have not been explored in detail.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States.
Monoanionic, bidentate-auxiliary-directed, cobalt-catalyzed C-H bond functionalization has become a very useful tool in organic synthesis. A comprehensive investigation into isolated organometallic intermediates and their reactivity within the catalytic cycle is lacking. We report here mechanistic studies of cobalt-catalyzed, aminoquinoline-directed C(sp)-H bond functionalization.
View Article and Find Full Text PDFJ Craniofac Surg
January 2025
Division of Plastic & Reconstructive Surgery, John H. Stroger Hospital of Cook County, Chicago, IL.
Median craniofacial hypoplasia is characterized by tissue deficiency of the midline facial structures and/or brain. Patients can present with a wide variety of facial differences that may or may not require operative intervention. Common reconstructive procedures include cleft lip and/or palate repair, rhinoplasty, and orthognathic surgery, among others.
View Article and Find Full Text PDFChaos
January 2025
Physics Institute, University of São Paulo-USP, São Paulo, SP 05508-090, Brazil.
This study focuses on the analysis of a unique composition between two well-established models, known as the Logistic-Gauss map. The investigation cohesively transitions to an exploration of parameter space, essential for unraveling the complexity of dissipative mappings and understanding the intricate relationships between periodic structures and chaotic regions. By manipulating control parameters, our approach reveals intriguing patterns, with findings enriched by extreme orbits, trajectories that connect local maximum and minimum values of one-dimensional maps.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!