Developments to Watch
SOME COLD WATER ON HOT-ENZYME R&D
A DECADE AGO, SCIENTISTS were thrilled by the discovery of single-celled creatures that thrive in hot volcanic vents under the sea. By learning how these hyperthermophiles remained stable above 100C--temperatures lethal to all other life forms--they hoped to create sturdy industrial enzymes that would make everything from sweeteners to cleansers. Now, researchers unlocking the critters' secrets question that approach.
Last fall, for the first time, University of Georgia biochemist Michael W. Adams and California Institute of Technology chemist Douglas C. Rees elucidated the atomic structure of an enzyme in a typical hyperthermophile, called Pyrococcus furiosus. Using a computer to correlate results from amino acid sequencing with data on the protein's crystal structure, they made a rendering of how characteristic protein structures are distributed in the enzyme (above). The big surprise: "There are no magical structures or new chemical reactions that account for the enzyme's stability," says Adams. Rather, its unique behavior arises from "an accumulation of subtle effects"--including how the 10,000-odd atoms are arranged. Adams now thinks it will be hard to rejigger conventional enzymes to withstand heat. To obtain enzymes that are active and stable at such temperatures, scientists will have to find them in nature and purify them.EDITED BY NEIL GROSS