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Wobble base pairs for inosine and guanine. A wobble base pair is a pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules. [1] The four main wobble base pairs are guanine-uracil (G-U), hypoxanthine-uracil (I-U), hypoxanthine-adenine (I-A), and hypoxanthine-cytosine (I-C).
These wobble base pairs are very important in tRNA. Most organisms have less than 45 tRNA molecules even though 61 tRNA molecules would technically be necessary to canonically pair to the codon. Wobble base pairing allows for the 5' anticodon to bond to a non-standard base pair. Examples of wobble base pairs are given in Figure 6.
A position of a codon is said to be a n-fold degenerate site if only n of four possible nucleotides (A, C, G, T) at this position specify the same amino acid. A nucleotide substitution at a 4-fold degenerate site is always a synonymous mutation with no change on the amino acid.
Protein translation involves a set of twenty amino acids.Each of these amino acids is coded for by a sequence of three DNA base pairs called a codon.Because there are 64 possible codons, but only 20-22 encoded amino acids (in nature) and a stop signal (i.e. up to three codons that do not code for any amino acid and are known as stop codons, indicating that translation should stop), some amino ...
A transversion usually has a more pronounced effect than a transition because the second and third nucleotide codon position of the DNA, which to a large extent is responsible for the degeneracy of the code, is more tolerant of transition than a transversion: transitions are more likely to be synonymous substitutions than transversions, as one ...
Other types of endogeneous DNA damages, given below with their frequencies of occurrence, include depurinations, depyrimidinations, double-strand breaks, O6-methylguanines, and cytosine deamination. DNA can be damaged via environmental factors as well. Environmental agents such as UV light, ionizing radiation, and genotoxic chemicals.
Nucleic acid thermodynamics is the study of how temperature affects the nucleic acid structure of double-stranded DNA (dsDNA). The melting temperature (T m) is defined as the temperature at which half of the DNA strands are in the random coil or single-stranded (ssDNA) state.
The transcription bubble is formed as a region of unpaired bases on one of the exposed DNA strands. The DNA is unwound and single-stranded at the start site, the location of RNAP binding. The DNA promoter interaction is interrupted as the RNA polymerase moves down the template DNA strand and the σ factor is released. [7]