Kollman notes that Miller's work on the RNA loop at 300 kelvins presents the first nanosecond-length, fully solvated, nonhelical RNA molecular dynamics trajectories. While the Ewald method is computationally intensive, it permits much longer simulation times. The RNA simulation ran for a nanosecond without instabilities, while the comparison cutoff methods resulted in instabilities within 300 picoseconds. A description of the work has been submitted to the Journal of the American Chemical Society . The group of J. Andrew McCammon has just completed a move from the University of Houston to the University of California, San Diego, where the researchers continue exploring problems in molecular recognition, binding, and reactivity.
AChE hydrolyzes the neurotransmitter acetylcholine to terminate synaptic transmission.
There is also practical interest in the use of inhibitors of AChE to manage Alzheimer's and other diseases. The AChE structure was solved in 1991 by Joel Sussman, Israel Silman, and colleagues at the Weizmann Institute in Rehovot, Israel. The active site in the structure is positioned in a channel in the molecule that appears too narrow to process acetylcholine rapidly. Last year, McCammon's group used computational methods to find an adjunct site at the bottom of the channel that may open up to facilitate processing. The group has also simulated the diffusional approach of the substrate to the enzyme.