Consider the genome of the bacterium Mycoplasma capricolum, which causes several
ID: 278401 • Letter: C
Question
Consider the genome of the bacterium Mycoplasma capricolum, which causes several types of respiratory ailments. There is a strong codon bias in this organism. Explain why this bias exists, and how it would be reflected in the translation of glutamic acid codons. For this amino acid in this organism, draw the complete molecular structure of nucleotide positions #34, 35 and 36 in the tRNA cognate for the codon that is used for this amino acid. Explain how the situation of glutamic acid codon and anticodon differs in Mycococcus leteus.
Problem #1 (25 points). 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 it would be reflected in the translation of glutamic acid codons. For this amino acid in this organism, draw the complete molecular structure of nucleotide positions #34, 35 this amino acid. Explain how the situation for glutamic acid codon and anticodon usage differs in Mycococcus luteus Lastly, explain how the "wobble" position of any anticodon can engage in non-Watson-Crick nucleotide pairing with the codon, while the other two positions follow W-C pairing rules. Be as chemically explicit as possible. , and 36 in the tRNA cognate for the codon that is used forExplanation / Answer
Q: Explain why this bias exists, and how it would be reflected in the translation of glutamic acid codons. Ans: Mycoplasma capricolum codon bias is due to genome having very low G+C content and rich in AT. This results in codon usage favoring synonymous codons with A and T, in particular in the wobble (3?) position. Codon bias in the AT-rich mycoplasmas is not limited to the third nucleotide position but is evident also in the first and second positions. Whereas Glutamic acid codons (GAA, GAG) are rich in GC. Hence capricolum uses GAT (RNA GAU) (instead of GAG, last G replaced with T) for Glutamic acid and GAA for aspertic acid instead of Glutamic acid, means Glutamic acid having only one codon in capricolum draw the complete molecular structure of nucleotide positions #34, 35 and 36 in the tRNA cognate for the codon that is used for this amino acid. C-U-A (tRNA anticodon loop) mRNA 5’---------G-A-U----------3’ Explain how the situation of glutamic acid codon and anticodon differs in Mycococcus leteus. Mycococcus leteus is a high GC content organism having 67% GC content over ecoli’s 51%. Most of the anticodons start with G or C. Hence it will have GAG codon coding for Glutamic acid, antocodon is CUC. Another codon of glutamic acid GAA replaced with GAG and codes for aspertic acid.