Mutations That Change Protein Structure
Definition
Mutation
A mutation is a change in the DNA sequence, which can alter the instructions for building proteins or regulating cellular processes.
- While some mutations are harmless, others can have significant effects on an organism’s health and development.
- Though they can occur in multiple ways, they can generally be classified into three main categories:
- Substitution: One base is replaced by another (also called point mutations)
- Insertion: One or more bases are added to the sequence.
- Deletion: One or more bases are removed from the sequence.
- Substitution mutations are the most common type of mutation.
- They're referred to as point mutations because they affect a single base pair.
How Mutations Affect Protein Structure
- The genetic code is a set of rules that translates mRNA sequences into amino acids, the building blocks of proteins.
- Each group of three bases, called a codon, specifies a particular amino acid.
- Mutations can alter this process in several ways:
- Silent Mutations
- The mutated codon still codes for the same amino acid due to the degeneracy of the genetic code.
- These mutations have no effect on the protein.
- Missense Mutations
- The mutated codon codes for a different amino acid.
- This can alter the protein’s structure and function, depending on the role of the affected amino acid.
- Nonsense Mutations
- The mutated codon becomes a stop codon, prematurely terminating protein synthesis.
- This usually results in a nonfunctional protein.
- Silent Mutations
