Resurrected Extinct Proteins Shows How Cellular Machines Evolved
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January 10, 2012

Resurrected Extinct Proteins Shows How Cellular Machines Evolved

 

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Joe Thornton and colleagues at the University of Oregon have worked out the process by which evolution added a component to a cellular machine, according to the Nature News Blog. Cells rely on “machines” made of multiple different protein components to carry out many vital functions in the cell, and molecular and evolutionary biologists have puzzled about how they evolved. Part of this machine is a ring of six proteins that threads through the membrane.

The team focused its research on a particular machine called the V-ATPase proton pump , which channels protons across membranes and is vital for keeping cell compartments at the right acidity. In animals and most other eukaryotes, this ring is composed of two types of protein. Thornton wanted to know how the machine evolved from the simple to the more complex form.

The team first scoured databases and pulled out 139 genetic sequences that encode the ring’s component proteins in a range of eukaryotic organisms. They then used computational methods to work backwards and find the most likely sequences of these proteins hundreds of millions of years ago, at key branching points on the evolutionary tree: just before and just after the ring increased in complexity. 
The team synthesized DNA that encoded these “ancestral” proteins and put it into yeast, which had had parts of its own proton pump deleted. The technique allowed Thornton’s team to test in yeast whether various combinations of ancestral proteins produced a working, proton-pumping machine.

The work reveals the pathway by which the two-component ancestral protein became a three-component one. The result challenges the assumption in biology that increased biological complexity evolves because it offers some kind of selective advantage. In this case, the more complex version doesn’t seem to work better or have any other obvious advantage compared with the simpler one; it is more likely that the two proteins were just corrupted by random mutation.

Thornton says that his and other groups will now probably use the same tools to dissect the evolution of more complex molecular machines.

The image above shows a RNA polymerase as it moves along the DNA molecule, copying its sequence of letters into ribonucleic acid.

The Daily Galaxy via nature.com and kurzweilai.net

Comments

"The result challenges the assumption in biology that increased biological complexity evolves because it offers some kind of selective advantage."

I'd like to know where the daily galaxy got this piece of information from. The research does not suggest this at all. This is not how it has been reported elsewhere. It leaves me wondering what the agenda of the people running this site is.

Joe Thornton and colleagues at the University of Oregon have worked out the process by which evolution added a component to a cellular machine. It is an assumption, may be true, may not be, or partly true, an objective scientist would attempt to validate or invalidate the studies and not simply through it under the conspiracy bus. Good effort was dedicated to the project, the best scientific interpretation of the data formed the conclusion. If you wish to prove it invalid, state your points and leave the preconceived bias at the door.

@Chris


I occasionally google the headlines and its normal to see the same post on at least 7 or 8 other websites. OH, and BUURRNNNNN!

The multiverse where every combination of everything exists must be real or else something must have created life on purpose. These molecular machines are intriguing and fascinating.

When will they find that nothing has a deeper purpose but just is as it is for no particular reason?

Two possible answers: Someday or never.


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