Motifs

Hairpin beta loop

beta-loop-beta. The loop is also called a reverse turn. UD. forms anti-parallel beta sheet.

Draw molecules H bonds. 2 amino acids make up the loop, these do not have H bonds.

helix-loop-helix

Example calcium binding or DNA binding.

Use right hand and point with index finger. Helix E starts from tip of index, loop is curled middle finger, helix F is the thumb.

greek key

4 beta strands anti-parallel from inside out. 4-1U-2-3. Big loop from strand 3 to 4. It is found in anti-parallel beta sheets.

beta-alpha-beta

Contains 2 parallel beta strands. The strands are connected by an alpha helix. 1BU-2A-3B. The alpha helix is above the plane and right handed.

Between α and β it has hydrophobic packing.

Helix and strands are parallel.