Elements of Protein Tertiary Structure

 

First look at secondary structures in 3D

 

 

The a-helix                                                                         The b-sheet

 

 

Some small structural motifs

 

 

The b-a-b unit                                                                    The b-b-b unit                                         The helix-turn-helix unit

 

These can be assembled into larger domains

 

 

There are four classes of overall protein folds, which may or may not contain named motifs, domains or elements

 

 

An ALL a Structure (albumin)                                         An ALL b Structure (antibody)

 

 

 

An a/b Structure (LDH)                                                 An a + b Structure (ricin A)