Biomolecules:
Proteins 2
Motifs
α helices and ß sheets combine to form motifs
that have common functions and are found in many proteins. Some examples are shown below.
|
The helix-turn-helix motif shown here is called an EF hand. This structure is often used to bind metal ions (like the Ca2+ ion shown here) and hold them in a specific orientation. |
α helices often pack against each other at angles of +20 or -50º, so that the ridges of one can fit into the grooves of another. |
|
The strands of a parallel ß sheet are often linked by an α helix in a ßαß motif. |
Several ß strands together can form a ß barrel. |
Motifs
