Texas Scientists Reach Out And Touch Molecules

"In order to design a new drug, you have to see how a chemical compound will fit. With this device not only will you see it, but you can feel it," said Dr. Edgar Meyer, a biochemist whose lab at Texas A&M University recently made a breakthrough in the ability to calculate the forces of movement within a molecule via an haptic device dubbed "Touché."

"Involving the extra sense of feeling for the chemist gives an advantage in designing drugs," he added.

Haptic, from the Greek word "to feel, "is a relatively new field of computer graphics.

Since its introduction in the 1960s, computer graphics have become much more attractive to the eye, but the information content is basically the same as 30 years ago, Meyer said, mainly because interactive devices like the mouse are inadequate.

"Haptics is the next step beyond the graphic interface - joining the computer and the human for the tactile, the touch, the feeling," he said. The device includes a hand-held baton which, when moved, interacts with an image on the computer screen to indicate what is being felt.

One application being studied elsewhere would enable a doctor to perform surgery via the Internet using the baton to "feel" the difference in soft tissue, hard tissue and bone, for example, on a patient who may be in another location but viewable on the computer screen.

Yet Meyer's lab looked even deeper.

With decades of molecular research experience aimed at human diseases, his team wondered how the molecule of a disease would "feel" when a substance was applied in order to block its ability to cause illness.

Simply speaking, a healthy molecule made up of various atoms has a mouth-like opening where a drug or inhibitor could bind. An uncontrolled, disease-causing molecule thus could be identified and blocked - an example of a drug acting at the molecular level, Meyer explained.

The inhibitor has to fit "like a lock and key," Meyer explained, to find the molecular structure of a target and then design blocks for it. The scientist has to "add and subtract atom to atom, eyeball to eyeball."

Dr. Stan Swanson, Experiment Station biochemist, was able to program the device to calculate the interaction with a large number of atoms while meeting "Touché's rapid cycle time.

Swanson figured out how to calculate a 50-atom drug molecule interacting with a biological receptor that has up to 600 atoms - a very large number of potential interactions that must be calculated in a very short period of time for "Touché to work. Jennifer Novak, a junior math major from Seymour, designed the computer's graphic interface for "Touché.

"Biological molecules are inheritantly very complex," Meyer said. "Molecules have bumpy surfaces, so you feel what it is like to go over the rough places in order to get it to fit into the right place. There is a noticeable repulsion when you are pushing again a molecule in the wrong place."

Meyer and his lab will now look at how other classes of molecules can be designed and ultimately hope to get "Touché into the hands of pharmacologists and medicinal chemists.

"Computers are here to help us serve mankind, and if we can address a serious challenge in the pharmacological industry for designing new drugs, then we can make their work easier and more productive," he said.