June 23, 2009

Protein can twist into a second shape

U.S. scientists have found a bacterial protein thought to exist in one 3-D shape can twist itself into a second form, depending on its chemical environment.

Researchers at The Scripps Research Institute, the University of California-San Diego and Ohio State University said they used a fluorescence technique to make their discovery. They said one of the bacterial protein's folded forms is active and the other is inactive, but the protein they studied -- Rop (repressor of primer), expressed in E. coli bacteria -- can easily morph from one state to another.

It has long been a puzzle as to how proteins, which can theoretically adopt an extremely large number of structures even with a single chain of amino acids, end up folding themselves to a well defined three-dimensional structural basin, Scripps Associate Professor Ashok Deniz said, adding a deeper understanding of how living systems use protein shape shifting to control cellular processes would allow better design of therapeutics that can alter the shapes in order to turn proteins on and off and control disease.

The study that included Jose Onuchic and Alexander Schug of the University of California-San Diego; Thomas Magliery and Jason Lavinder of Ohio State University; and Yann Gambin, Edward Lemke and Allen Ferreon of Scripps Research appeared in the June 8 early online edition of The Proceedings of the National Academy of Sciences.