Aims

• To emphasise the modular structure of many proteins.
• To look at arrangements of protein secondary structure elements and how proteins can be classified according to their structure.

Objectives

After this lecture you will:

• know that proteins often consist of structural domains;
• be aware of some common secondary structure motifs and of alternative structural classification hierarchies, including CATH and SCOP.

Supplementary Material

Peer Bork has collected some cartoons of modular extracellular proteins.

SCOP is a hierarchical structural classification of proteins. I recommend that you read the detailed description of SCOP.

CATH is a hierarchical classification of protein domain structures, which clusters proteins at four major levels, Class(C), Architecture(A), Topology(T) and Homologous superfamily (H). I recommend that you read the detailed description of CATH.