نتایج جستجو برای: nucleic base

تعداد نتایج: 322142  

Journal: :Journal of the American Chemical Society 1998
Tracy J Matray Eric T Kool

Noncovalent interactions between aromatic nucleobases are the major stabilizing forces which contribute to the structural integrity of duplex DNA and RNA.1-3 However, base pairing in nucleic acids is a consequence of more than just hydrogen bonding alone. The predictive success of nearest neighbor analysis,4 along with “dangling base” measurements which show duplex stabilization in the absence ...

2011
Thomas E. Edwards Pavol Cekan Gunnar W. Reginsson Sandip A. Shelke Adrian R. Ferré-D’Amaré Olav Schiemann Snorri Th. Sigurdsson

Previously, we developed the deoxycytosine analog Ç (C-spin) as a bi-functional spectroscopic probe for the study of nucleic acid structure and dynamics using electron paramagnetic resonance (EPR) and fluorescence spectroscopy. To understand the effect of Ç on nucleic acid structure, we undertook a detailed crystallographic analysis. A 1.7 Å resolution crystal structure of Ç within a decamer du...

Journal: :The Biochemical journal 1969
V M Craddock

1. The effect of administration of various dosages of dimethylnitrosamine on the extent of methylation of liver and kidney nucleic acids in the intact rat was studied. Methylation of liver nucleic acids was linearly related to the dosage, but decreasing the dose produced relatively less lowering of the extent of alkylation of kidney nucleic acids. 2. The rates of disappearance of 7-methylguanin...

2015
Elzbieta Sochacka Roman H. Szczepanowski Marek Cypryk Milena Sobczak Magdalena Janicka Karina Kraszewska Paulina Bartos Anna Chwialkowska Barbara Nawrot

2-Thiouracil-containing nucleosides are essential modified units of natural and synthetic nucleic acids. In particular, the 5-substituted-2-thiouridines (S2Us) present in tRNA play an important role in tuning the translation process through codon-anticodon interactions. The enhanced thermodynamic stability of S2U-containing RNA duplexes and the preferred S2U-A versus S2U-G base pairing are appr...

Journal: :Quarterly reviews of biophysics 2017
Niklas Bosaeus Anna Reymer Tamás Beke-Somfai Tom Brown Masayuki Takahashi Pernilla Wittung-Stafshede Sandra Rocha Bengt Nordén

We have discovered a well-defined extended conformation of double-stranded DNA, which we call Σ-DNA, using laser-tweezers force-spectroscopy experiments. At a transition force corresponding to free energy change ΔG = 1·57 ± 0·12 kcal (mol base pair)-1 60 or 122 base-pair long synthetic GC-rich sequences, when pulled by the 3'-3' strands, undergo a sharp transition to the 1·52 ± 0·04 times longe...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Michael T Sykes Michael Levitt

We show that RNA base pairs have variable stability depending on their degree of solvation. This finding has far-reaching biological implications for nucleic acid structure in a partially solvated cellular environment such as inside RNA-protein complexes. Molecular dynamics simulations of partially solvated Watson-Crick RNA base pairs show that whereas water serves to destabilize a base pair by...

Journal: :Cell 2015
William E. Salomon Samson M. Jolly Melissa J. Moore Phillip D. Zamore Victor Serebrov

Argonaute proteins repress gene expression and defend against foreign nucleic acids using short RNAs or DNAs to specify the correct target RNA or DNA sequence. We have developed single-molecule methods to analyze target binding and cleavage mediated by the Argonaute:guide complex, RISC. We find that both eukaryotic and prokaryotic Argonaute proteins reshape the fundamental properties of RNA:RNA...

2015
Christopher Cozens Hannes Mutschler Geoffrey M. Nelson Gillian Houlihan Alexander I. Taylor Philipp Holliger

Information-bearing nucleic acids display universal 3'-5' linkages, but regioisomeric 2'-5' linkages occur sporadically in non-enzymatic RNA synthesis and may have aided prebiotic RNA replication. Herein we report on the enzymatic synthesis of both DNA and RNA with site-specific 2'-5' linkages by an engineered polymerase using 3'-deoxy- or 3'-O-methyl-NTPs as substrates. We also report the reve...

2010
André Eichert Katja Behling Christian Betzel Volker A. Erdmann Jens P. Fürste Charlotte Förster

'Locked nucleic acids' (LNAs) are known to introduce enhanced bio- and thermostability into natural nucleic acids rendering them powerful tools for diagnostic and therapeutic applications. We present the 1.9 Å X-ray structure of an 'all LNA' duplex containing exclusively modified β-D-2'-O-4'C-methylene ribofuranose nucleotides. The helix illustrates a new type of nucleic acid geometry that cont...

Journal: :Nucleic acids research 1999
V A Efimov A A Buryakova O G Chakhmakhcheva

Two types of oligonucleotide mimics relative to peptide nucleic acids (PNAs) were tested as probes in nucleic acid hybridisation assays based on polyacrylamide technology. One type of mimic oligomers represented a chimera constructed of PNA and phosphono-PNA (pPNA) monomers, and the other one contained pPNA residues alternating with PNA-like monomers on the base of trans -4-hydroxy-L-proline (H...

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