Ribosomes, RNA and pseudoknots

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In summary, the article discusses how Danish researchers have solved the puzzle of how viruses are produced by a cell. They found that the virus invades the cell and uses its RNA, which resembles the human RNA, to trick the ribosomes into producing the proteins needed for the construction of the virus. The presence of pseudo-knots in the viral RNA causes the ribosomes to sometimes slip backwards and read a different RNA sequence, resulting in the production of a different protein. The strength of the pseudo-knots determines how often this backwards slipping occurs, and the different protein formed is still able to construct the virus, with potentially harmful consequences for the host organism. This process is how many viruses, such as HIV, manipulate the cell into producing something
  • #1
The article Danish researchers solve virus puzzle
describes how physicists and biologists work together to examine how viruses are produced by a cell.

As far as I understand, every human cell has RNA which contains the 'recipe' on how to build proteins. The human cell also contains ribosomes that read the RNA and produce proteins.

Now, the virus invades the cell, leaves its RNA in the cell. The trick: because the viral RNA resembles the human RNA, the ribosomes read the viral ribosomes and produce proteins for the construction of a virus.

But the viral RNA has in contrast to the human RNA some curls, called pseudo-knots. The ribosomes have to unravel the pseudo-knot first. While doing this, they sometimes slip backwards such that the recipe is read in a different way.

Now my question about the following passage in the article:
During this process the ribosome sometimes slips backwards and, like the letters making up a word, it now reads a new RNA sequence and hence uses another recipe to construct the protein. The researchers have found that the stronger the pseudoknot the more often this backwards slipping happens. The different protein formed is the protein needed by the virus, with possible serious consequences for the hosting organism. This is the manner in which many vira, e.g. HIV, trick the cell into producing something which it never would have done otherwise.

I wonder about the sentence The different protein formed is the protein needed by the virus. Why can this different protein also be used to construct the protein?
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  • #2
Oops, my question is of course:
Why can this different protein also be used to construct the virus?
  • #3

The different protein formed by the backwards slipping of the ribosome is the protein needed by the virus because the viral RNA contains specific instructions for the production of that protein. The ribosome, while trying to unravel the pseudoknots, may slip backwards and read a different sequence of RNA, resulting in the production of a different protein than what the host cell would normally produce. In the case of viruses, this different protein is essential for their reproduction and survival within the host cell. This is how viruses manipulate the host cell's machinery to produce proteins that benefit their own survival and replication. The production of a different protein than what the host cell would normally produce can have serious consequences for the host organism, as it can disrupt normal cellular functions and potentially lead to disease. Overall, the presence of pseudoknots in viral RNA allows for this trickery of the host cell's ribosomes, ultimately aiding in the production of proteins necessary for the virus's survival.

1. What is the function of ribosomes?

Ribosomes are responsible for protein synthesis in the cell. They read the genetic code carried by messenger RNA (mRNA) and use transfer RNA (tRNA) to assemble amino acids into polypeptide chains, which form proteins.

2. How is RNA different from DNA?

RNA is a single-stranded molecule, while DNA is double-stranded. RNA also contains the sugar ribose, while DNA has deoxyribose. Additionally, RNA uses the base uracil instead of thymine found in DNA.

3. What is the role of pseudoknots in RNA?

Pseudoknots are complex structures formed by RNA molecules that are crucial for their function. They help to stabilize the shape of RNA molecules and play a role in regulating gene expression and protein synthesis.

4. How do ribosomes know where to start and stop protein synthesis?

Ribosomes use a start codon (AUG) on the mRNA strand to initiate protein synthesis. They then continue to read the mRNA sequence until they reach a stop codon (UAA, UAG, or UGA), which signals the end of the protein chain.

5. Can ribosomes make mistakes during protein synthesis?

Yes, ribosomes can make mistakes during protein synthesis. These errors, known as mutations, can lead to changes in the amino acid sequence of a protein, potentially affecting its function. However, cells have mechanisms in place to detect and correct these mistakes to maintain proper protein production.

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