4. The year is 2442. Protein engineering and molecular biology have became incre

Question

4. The year is 2442. Protein engineering and molecular biology have became incredibly powerful and all diseases are cured. Or so you thought, as your previous cell culture now has cancer because of your horrendous lab habits. You fix the issue with the cells, sequence all their chromosomal DNA for fun and start looking through their genome. You find a sequence that catches your eye that has the general setup:

The start and stop codon are in the same translation frame, so this appears to be a single gene that makes a single protein. No other stop codons are in between the start and stop codons identified in the figure above. In the future, all proteins in all organisms have been identified and described in extensive detail on the internet. You translate the DNA sequence into an amino acid sequence and search to see what it is. Nothing shows up in your online search, and you are shocked. You get excited, thinking that you discovered a new protein that was somehow missed by previous biochemists. You use mass spectrometry to quantify any amount of each protein in a biological sample. Based on the amino acid sequence you translated, you try to see how much of this protein is in the cells. You find none. Confused, you sequence all the mature mRNA in the cell to find any that have the same sequence that was in the DNA. You find a somewhat similar mRNA that is 1250 nucleotides long. The open reading frame of this mRNA is a joined transcription of the first 300 base pairs and the last 450 base pairs of the DNA sequence, with nothing in between these two regions. You cannot find any mature mRNA that corresponds to the middle 1251bp of the genomic DNA. In 1-3 sentences, give an explanation for this:

Your cell culture is made of human cells, and you wonder what if similar chromosomal sequences can be found in other organisms. You look online for genomic sequences from Saccharomyces cerevisiae (yeast) and identify a homologous gene to this. The first 300 base pairs and last 450 base pairs of the genomic DNA sequence are almost identical to the sequence from your cells, but the middle region has a completely different sequence. You find a paper that sequenced the mature mRNA of this gene from yeast, and found that it similarly lacks the center region of the gene while maintaining the outer regions in the same format. In relation to the sequence found in your human cell culture, will the protein have a similar or different amino acid sequence? Do you expect the gene to have a similar or different function?

Based on the RNA sequence for the gene that you identified earlier, you finally track down the protein that this gene produces. You gasp in excitement: it is a motor protein. You recombinantly express this gene purify the motor protein in hopes of it being the next top-tier racing molecule. You find that it is composed of two distinct amino acid chains that are joined by disulfide linkages. This does not exactly match the mRNA sequence, which predicts that the protein would be composed of a single amino acid chain that is 250 amino acids long. However, one chain is composed of the first 150 amino acids of the predicted amino acid sequence and the other is composed of the final 100 amino acids. In 1-3 sentences, give an explanation for this:

Explanation / Answer

Ans- in first part the mRNA found will be due to frame shift mutation in which the transcription of the gene changes due to shifting in the reading of the frame.

In second part the gene will be having different amino acid sequence and a comoletely diffrent function but if the mRNA is arranged in such a manner that the codon will be different but codes for similar amino acid then in that case amino acid sequence will be similar along with similar function.

In third case the reason may be as there are some proteins which can't be produced in a single strech and sometimes there are protein remodeling which may be responsible for this.

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