Daily experience shows that the “arrow of time” decidedly points forward. The laws of physics agree. The second law of thermodynamics dictates that the universe will proceed toward greater entropy, that is, in the direction that increases the number of possible arrangements the universe can adopt. Events “go” in only one direction: toward higher entropy. The passage of time that marks these occurrences therefore goes in one direction as well.
Very few have figured out how to undo the effects of reactions that have progressed to a low entropy state. One exception is a team of researchers from the University of California, Irvine, the University of Western Australia and Flinders University, who have found a way to flip the direction of time’s arrow: they have unboiled an egg. (1)
Boiling an egg denatures the proteins that comprise the egg itself. To refold these unfolded proteins means to recreate the chemical bonds that once held the protein in its original shape. Currently, a process called dialysis is used in the food industry to refold unfolded enzymes (proteins that assist and speed up chemical reactions). (2) This process, however, can take up to four days. Interestingly, a new method published in ChemBioChem refolds denatured proteins within minutes using extremely high rotational speeds.
After boiling an egg white for 20 minutes, the researchers took a sample of the egg white, diluted it, then spun it in a vortex fluid device (VFD) which rotates solutions at an angle, and at high speeds. By analyzing the structure of specific proteins like a small lysozyme – which breaks down bacterial cell walls – as well as larger proteins, the researchers found that the shear stress introduced by high speeds in the VFD was enough to refold unfolded proteins. For example, after only two and a half minutes in the VFD, lysozymes in the boiled egg white were recovered in almost original form and its hydrolyzing (bond-breaking) activity was restored. (2, 3)
VFD refolds proteins by allowing an individual protein’s strands to separate from strands belonging to other proteins in the sample. This way, each protein is free to resume its original shape. For example, when egg whites are boiled, the bonds holding together the proteins within the egg white are broken. This leaves strands of unfolded protein that, given their chemical makeup, still have the ability to bond to nearby proteins. As a result, they’re “sticky”: they bond with surrounding proteins. When they do, the result is a hardened egg white. However, when VFD spins these denatured proteins at high speeds, it forces the strands of various proteins that have bonded together to separate. It thereby frees each protein to use its bonds to resume its own original shape. (3)
… the new method has certainly created a new symmetry in human life, for the arrow of time has – for those brief moments in a protein’s history – reversed …
And though it was a relatively straightforward process to refold the lysozyme, the VFD method still needed to be “personalized” for larger proteins; in fact, the researchers say that the method should be tailored to each protein that it restores. For example, the speed and stress that must be applied by the VFD depends on the size of the protein. In addition, larger proteins require that certain small molecules be attached to the end of the unfolded protein in order to separate the ends of the protein by their weight. When undergoing VFD, this separation by weight allows the VFD-induced shear stress to mimic natural cellular folding by beginning the refolding in specific regions of the protein instead of all at once. (2)
The results have profound implications for industries that create multitudes of proteins a day, like those involved in cancer treatments, in research, or food industries. In these manufacturing processes, proteins can accumulate on instruments and on other areas, a phenomenon which makes the proteins unusable. With VFD technology, those proteins can be resuspended to become functional and reusable, saving time and money in the process. (1) But no matter how it’s used, the new method has certainly created a new symmetry in human life, for the arrow of time has – for those brief moments in a protein’s history – reversed: the VFD method is a protein time machine.
- Bruzek, Alison. “How Unboiled Eggs Could Help Fight Food Waste.” the salt. NPR, 2 Feb. 2015. Web. 13 June 2015.
- T. Z. Yuan, C. F. G. Ormonde, S. T. Kudlacek, S. Kunche, J. N. Smith, W. A. Brown, K. M. Pugliese, T. J. Olsen, M. Iftikhar, C. L. Raston, G. A. Weiss. “Shear-Stress-Mediated Refolding of Proteins from Aggregates and Inclusion Bodies.” ChemBioChem 16.3(9 Feb 2015): 393-396.
- Orlowski, Aaron. “How UCI Scientists Figured out How to Unboil an Egg, and What That Means for Cancer.” The Orange County Register. Freedom Communications, Inc., 27 Jan. 2015. Web. 08 Aug. 2015.
Atrin Toussi is the Primary Research Editor for Brevia. She can be reached at firstname.lastname@example.org.