Amino acids and proteins

Why this matters

Dentine, cementum, periodontal ligament and bone are built on one protein. Enamel is shaped by another and then dismantles it deliberately. Saliva protects teeth with a third set. When you sterilise an instrument you are destroying protein structure on purpose. Almost everything you will do clinically either depends on proteins working or on making them stop.

The big picture

Twenty amino acids differ only in a side chain. Link them with peptide bonds and the sequence is fixed — that is the primary structure. The chain then folds, because those side chains attract and repel water and each other. Shape is what gives a protein its function, so anything that destroys shape destroys function, even though every peptide bond survives.

The 12 cards in this lesson

1. 01Shape is what a protein is for
2. 02One carbon, four attachments
3. 03The side chain decides where the residue sits
4. 04Essential means dietary, not important
5. 05The peptide bond, and why it is stiff
6. 06Four levels of protein structure
7. 07Helices and sheets: the two standard patterns
8. 08Collagen: why glycine must be every third residue
9. 09Clinical alert — in the lesson
10. 10Folding: the sequence carries the instructions
11. 11Denaturation: shape destroyed, sequence intact
12. 12The proteins you will actually meet

You have got it when

You are ready to continue when you can explain why glycine must sit at every third position in collagen, why vitamin C deficiency loosens teeth, and what denaturation destroys and what it leaves intact.