M5. The three-dimensional structure of a protein is critical to its function.

Student Outcome: M5.1

Explain how the three-dimensional structure of proteins can facilitate recognition and binding of specific molecules, including enzymes and substrates, and cell membrane receptors and hormones.

Process of Protein Formation

String of amino acids is formed

This video shows the formation of a peptide bond. Pay attention - there is no voice-over!

Coiling and folding of parts of the chain occurs

Here are two videos showing the formation of alpha helices and beta pleats (ie the secondary structure of proteins). Note: not for the easily distracted!

Final folding of whole chain to form 3D shape

This video starts at the beginning with an amino acid chain and then incorporates the three steps of protein folding mentioned above.

Two or more proteins fold together to produce final molecule
Examples: complex protein - haemoglobin; simple protein - insulin

Here is a really simple link about protein folding. It shows each of the stages above very simply. It is called Biological Animations and you need to click on the "protein organisation" link.

This fool is talking about the function of proteins. Video quality is poor but unless you can do better, it's all I have.

To do the many different jobs that proteins do being "in the right shape" really does matter.

Having the correct shape is vitally important in phenomena as diverse as the fit of a hormone into a receptor,
	the binding and chemical alteration of a substrate by an enzyme,
or the binding of an antibody to an antigen.
Here is the dry version of protein folding:	Here is a more oesoteric version:

If these two videos don't explain things, try this interactive flash production. Some details are not needed (e.g. chaperone proteins) but it is still interesting.

Here is a Google Video but it is about how bacteria created their flagellum - a long complex structure made up of proteins. It shows in great detail how it is assembled and how the struture of the protein is important to its function. It's long - about 30 minutes and very technical but amazing to watch. Even the complexity of the first still is amazing.

This is my presentation on sections M5, M6 and M1 of the syllabus.