When the American Crystallographic Association held its first meeting in 1950, only a handful of scientists in the world were studying structures of molecules such as proteins.

Today, several thousand people are doing work in a matter of hours that used to take years to complete a generation ago, said Charles Simmons, a University of Hawai'i-Hilo chemistry professor who this week is co-chairing with UH-Manoa professor Karl Seff the ACA's first meeting in Hawai'i since 1979.

Many of the 1,000 people attending the ACA meeting are first-time visitors to the state. About 40 percent of the attendees are from Canada, Europe, Russia, Korea and South America, Simmons said, noting that the international representation is believed to be the largest ever for an ACA meeting.

The six-day meeting at the Sheraton-Waikiki ends today. Next year's ACA meeting will be held in Salt Lake City.

The advancement of computers and crystallographic equipment, such as the Bruker AXS diffractometer, which generates X-rays used to measure protein crystals and collect data quickly, allows crystallographers to open new doors for drug designers, Simmons said. The research could produce pills and vaccines for AIDS and avian flu, Simmons said.

"It's like a lock and key," he said of the scientists working in tandem with drug designers. "If you know the structure of the lock, you can design a key to fit and unlock the lock."

Reach Rod Ohira at rohira@honoluluadvertiser.com.