CORVALLIS, Ore. There's nothing like a new pair of eyeglasses to bring fine details into sharp relief. For scientists who study the large molecules of life from proteins to DNA, the equivalent of new lenses have come in the form of an advanced method for analyzing data from X-ray crystallography experiments.
The findings, just published in the journal Science, could lead to new understanding of the molecules that drive processes in biology, medical diagnostics, nanotechnology and other fields.
Like dentists who use X-rays to find tooth decay, scientists use X-rays to reveal the shape and structure of DNA, proteins, minerals and other molecules.
As X-rays pass through atoms they reflect distinctive patterns, which reveal what atoms are present and how atoms are bonded to each other. However, some data are typically discarded because of concerns over quality. In particular, data derived from edge regions of the pattern although very important for understanding the details of structure are often overwhelmed by the random errors associated with a weak signal in the midst of a lot of background noise.
Oregon State University biophysicist Andy Karplus and his colleague Kay Diederichs at the University of Konstanz in Germany have now proven that useful information can be gleaned from data that have about five times the noise level that was previously considered acceptable.
"The criteria that have been used in the past are way too conservative," said Karplus. "These data that people have been throwing out are actually good."
The bottom line for crystallographers is the accuracy of their molecular models. The better the model, the better it will predict the pattern created by X-rays passing through a molecule, and the better it will be to develop new drugs and nanotechnologies that operate at the molecular scale.
The new method may be the most important conceptual advance in the past 20 years in h
|Contact: Andrew Karplus|
Oregon State University