Researchers reveal insights into hidden world of prote...(e a molecule called a chaperone to fold ...)

"Many of the proteins that have these complex folds are the most important ones for life," Frydman said. "The proteins that control the cell cycle, tumor suppressers and the proteins that control the shape of the cell are dependent on chaperonins to get to the folded state.

"If the chaperones don't work well, then all these proteins that have been made become toxic," she said.

TRiC, like all chaperonins, consists of a double-ringed structure that gives it a barrel shape. One ring opens to admit the raw protein into the inner recesses of the folding machine, then closes tightly while, inside the chaperonin "black box," the mysteries of molecular origami unfold-or, more correctly, fold. Upon completion of the folding, the ring at the other end opens up to push out the finished product.

"It is really like a nanomachine. It closes off, the protein is trapped inside and something-we don't understand what-happens inside this chamber, and the protein comes out folded," Frydman said. "It is a very complex mechanism."

The rings at each end of the barrel have to synchronize their actions for the sequence of events to happen correctly.

"We don't know how the rings coordinate," Frydman said. "What we have is evidence that this machine works like a two-stroke motor, so that opening one ring closes the other, and when that other ring opens, the first one is closed."

Timing is critical because if a protein does not stay in the chaperonin long enough, it may not have time to fold properly. Conversely, if it lingers too long, it may also fold incorrectly. And sometimes proteins are not made correctly by the ribosome
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