Leeches - used in the nineteenth century as a popular remedy for many afflictions-produce a molecule that prevents blood from clotting. Drugs that inhibit blood coagulation in heart-attach patients are now being clinically tested because chemist Alexander Tulinsky solved the structure of this molecule - called hirudin - and how it inactivates coagulation.

Although clots can save lives by preventing blood from leaking out of the body, they also kill more than half a million Americans a year. Tulinsky's entire distinguished career studying molecules - he loves "big molecules" - led to an understanding of how clots might be dissolved through a revolutionary method called X-ray crystallography. Tulinsky pioneered the use of the process to x-ray blood protein crystals that he grows in his lab. The resulting pattern is converted into a map of the molecule's atomic arrangement. Tulinsky explains that "when you know the positions of atoms in a molecule, you can uncover how they achieve something, such as blood coagulation."

Tulinsky's work, lauded by Novel-prize winning scientists at his recent retirement, will be continued by Jim Geiger, who was attracted to MSU because of the x-ray facility. At the facility's core are two mirrors that produce intense x-ray beams. Manufactured by OSMIC, a Michigan company, the mirrors were first installed at MSU and are now available commercially throughout the world. "Our lab is state of the art," says Tulinsky. "Protein crystallography is revolutionizing bioloby. It crosses biochemistry, chemistry, physics, and biology and attracts the brightest young students in structural bioloby. Recently, protein crystallography solved the problem of the onset of the AIDS infection."