October 16, 2001

Pollen binding may be key to new molecular superglue

Daphne Preuss, a researcher and professor in the Department of Molecular Genetics and Cell Biology at the University, has isolated a new molecule from a weed's sex organs. Because it binds selectively, this molecule is being used to develop a kind of super-specific microscopic superglue. Machines adept at using this new glue could create a new generation of tiny computer chips, making computers even faster.

Preuss's discovery stemmed from an intense study of the pollination patterns of Arabidopsis thaliana, a plant in the mustard family related to cabbages and radishes. Pollen is plant specific — it will only stick to a stamen of its own species to fertilize it. But why? This was Preuss's initial question. “We wondered what happened when the wind blows, and insects walk around," Preuss said in a September press release.

Preuss and her team proceeded to investigate this question in the lab with Arabidopsis by rubbing and generally manipulating the plant's stamens with pollen and other bits and pieces to see what might stick. Only Arabidopsis pollen stuck to Arabidopsis stamen, and only petunia pollen stuck to petunia stamen; in Preuss' tests, the pollen of one plant only stuck to stamens of the same species. This was an immediate indicator of pollen specificity.

“We demonstrated that the wrong stuff rubs off easily, while the right stuff sticks tight, and we wanted to measure it," Preuss said in the release. Measuring why the pollen specifically acts as an adhesive at the molecular level was the next step.

Working with David Grier, a physicist, and Milan Mrksich, an associate professor of chemistry (both of the U of C), Preuss reasoned that her results implied a lock-and-key molecular mechanism.

The species' pollen represents the “key" that fits only the molecular “lock" of the stamen of the same species. This idea has been seen before in the behavior of enzymes.

Over the summer, Preuss published results of the Arabidopsis genome and noted that among the mapped genes was one “cluster" that codes for enzymes called lipases, which to eat away at lipids, and oleosins, which eat away at proteins. She believes that it is these enzymes that are involved in a plant-specific enzymatic reaction during pollination that causes the cells of the pollen to somehow fuse with the cells of the stamen.

The very specific enzymatic reaction in Preuss's proposed mechanism could be applied as an adhesive since the pollen binds tightly to the stamen.

However, it is the specificity of these new molecules that makes them most interesting to scientists. Presumably there are many different molecules that behave like Arabidopsis pollen because there are so many plant species. The possibilities for this new superglue based on the pollen mechanism are increased by its intense specificity; an adhesive based on this research could bind only to certain areas.

This discovery may have positive repercussions in the medical and nanotechnological fields since computer chips, which contain tiny printed circuits, could be enhanced by such a specific binding molecule.