Ricin comes from the seeds of castor bean plants and its claim to fame is that it was the poison used to kill the Bulgarian dissident Georgi Markow in London. Just as in a good James Bond story the toxin was injected from the tip of an umbrella as Mr Markow was waiting for a bus.
This is a picture of seeds containing abrin (red/black) and ricin.
They are often used to make necklaces. Chewing on these seeds can be fatal.
Ricin site at Cornell University
A picture of ricin.
I have also worked on the cell binding portion of another toxin called Shiga-like Toxin (SLT). It is quite an 'attractive' molecule as it is shaped like a doughnut and is made up of 5 identical subunits.
A picture of SLT B chain.
I am now working with Diphtheria toxin (the B fragment).
A picture of DT.
The above pictures were created using the excellent program Rasmol (written by Roger Sayle). With Rasmol you can rotate a molecule to any orientation and view it with ball and sticks, backbone, ribbons etc and in various colours. Amino acids can be identified with a simple click. The view can be exported as a *.bmp, *.gif etc.
A good starting place for other files is Molecules R Us.
Or you could try SCOP - the Structural Classification of Proteins.
A page of links to various Companies is under construction.
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