Consider the genome of the bacterium Mycoplasma capricolum, which causes several
ID: 90411 • Letter: C
Question
Consider the genome of the bacterium Mycoplasma capricolum, which causes several types of respiratory ailments in humans. There is a strong codon bias in this organism. Explain why this bias exists, and how is would be reflected in the translation of glutamic acid codons. For this amino acid in this draw the complete molecular structure of nucleotide positions #33, 34, 35, and 36 in the tRNA cognate for the codon that is used for this amino acid. Explain how the situation for glutamic acid codon and anticodon usage differs in Mycococcus luteus. Be very explicit.Explanation / Answer
Mycoplasma capricolum contains a lot of GC codons, as to complete this codon there is A or T synonymous codons. Mycoplasma capricolum tend to select optimal codons. These two statements suggest the situation for the bacterium, codon usage bias, this happens when there is differences in the frequency of occurrence of synonymous codons.
The gene sequences or the DNA in them leads to their biological function, the overall usage of codon trends represents also their evolutionary direction. The synonymous codon usage patterns is comes from their GC and AT skews estimate nucleotide composition, thus protein consideration is also become a problem.
Genetic studies have indicated that the synonymous site in a codon or the third position is subject to weak selection. From here there is a synonymous codon usage bias.
Naturally Glutamic acid is encoded by the codon GAA and GAG. Now looking into the termination codons naturally present are UAA, UGA, UAG.
IN DNA, the universal genetic code categorized TGA, TAA, and TAG as stop codons, in case of protein translation. In Mycoplasma capricolum, the preferential use of a particular stop codon is highly biased. As the TAG is much conserved, the optimal codons is not useful in that, but other two are having synonymous codons, A could be replaced easily. TAA in case of bacteria is most preferred stop codon.
In case of Glutamic acid synthesis this could be a potential trouble for the bacterium, here the glumatic acid codon could swap the stop codon sequence of UAA or UGA to a glutamic acid codon, U could be replaced with a G in place. This biasness could be harmful for the protein translation.