Imagine a scenario where you have the freedom to commit any number of mistakes without being corrected (The first part is right for researchers!).
Well the RNA biomolecule has this privilege, lets learn how?
Each cell divides into two and each will have a copy of the things be it an organelle or the genetic material. The time and place of mistakes in cell division happens in replication. Replication is the process of preparing daughter DNAs (new strands) from the parental strand (original strands).
A polymerase (Pol) is an enzyme that helps to make copies of nucleic acids. Based on the nucleic acid, they are either DNA polymerase (DNA pol) or RNA polymerase (RNA pol).
Polymerase always follows a cardinal rule while copying the string of base commands:
place C against G (vice-versa)
place T for A (vice-versa) in DNA
place U for A (vice-versa) for RNA.
The copying mechansim of polymerize to make a fresh DNA copy from the original one is polymerization activity.
If the polymerase unfollows the above cardinal rule and makes a mispair of A to G or C to T (termed as illegitimate base pairing) it is called a mistake or mutation in bioscience. The polymerase usually has a structural and inbuilt command that will rectifiy this immediately. This process is termed as proofreading activity and it works by moving a step back and deleting the mistake.
RNA polymerase which is used to make a copy of RNA do not have proofreading activity.
Without proofreading, RNA tends to create changes, resulting in variant copies of the original RNA. Thus, the lacking of proofreading feature makes the RNA is more prone to change than DNA.
Only certain type of viruses have RNA as their genetic material. In absence of proofreading the RNA viruses mutates during replication creating more dangerous strains.
Developing antivirals for RNA viruses is a heculian task, taking few years (if you are extremely lucky!). Antivirals are substances that kill or block the virus from its activity. Anivirals normally work by binding to a particular region (domain) which the virus uses to bind with the host cell.
Imagine you develop an antiviral to bind to a particular location on the virus after years of work. The mutated virus have a different binding site preventing the antiviral to "lock" with it and disable the virus. There goes your work!
HIV, HIN1, SARS-CoV-2 are few examples of RNA virus - hope you got the idea of how dangerous they can be. If not, Ask 2020!
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