The Central Dogma
DNA → RNA (multiple types) → Proteins
DNA → mRNA transcript
mRNA → Protein
- tRNA match to mRNA in chunks of 3 nucleotides.
- Ribosomal RNA holds mRNA still so tRNA can find its match.
- RNA maps to amino acids - multiple RNA chunks per amino acid, to be tolerant to possible mutations.
- Amino acids link together via peptide onds.
- Primary structure - amino acid chain (polypeptide)
- Secondary structure - folded structure within a polypeptide
- Tertiary structure - 3D structure of polypeptide
- Quartenary structure - multiple polypeptide chains joining together to make a protein
When proteins are denatured, they go from quartenary structures to tertiary structures.
Traditional vaccines: have a bit of the virus (live or killed).
- Example: smallpox is a live virus
- We don’t use live virus much anymore
mRNA Vaccine for Covid: Injects mRNA transcript of Covid spike proteins.
- Cells express it into a protein, immune system mounts a response.
- Why mRNA vaccine for Covid?
- Covid mutates/evolves very fast, so it’s hard to pin down one version to include in the vaccine.
- Even a weakened version of the virus could be dangerous to immunocompromised people.
- Because it’s a coronavirus, future mutations should also have the spike protein.