By converting their data into sounds, scientists discovered how hydrogen bonds contribute to the lightning-fast gyrations that transform a string of amino acids into a functional, folded protein. Their report, in the Proceedings of the National Academy of Sciences, offers an unprecedented view of the sequence of hydrogen-bonding events that occur when a protein morphs from an unfolded to a folded state. "A protein must fold properly to become an enzyme or signaling molecule or whatever its function may be -; all the many things that proteins do in our bodies," said University of Illinois Urbana-Champaign chemistry professor Martin Gruebele, who led the new research with composer and software developer Carla Scaletti.
Misfolded proteins contribute to Alzheimer's disease, Parkinson's disease, cystic fibrosis and other disorders. To better understand how this process goes awry, scientists must first determine how a string of amino acids shape-shifts into its final form in the watery environment of the cell. The actual transformations occur very fast, "somewhere between 70 nanoseconds and two microseconds," Gruebele said.
Hydrogen bonds are relatively weak attractions that align atoms located on different amino acids in the protein. A folding protein will form a series of hydrogen bonds internally and with the water molecules that surround it. In the process, the protein wiggles into countless potential intermediate conformations, sometimes hitting a dead-end and backtracking unt.