Featured Research

from universities, journals, and other organizations

How life may have first emerged on Earth: Foldable proteins in a high-salt environment

Date:
April 5, 2013
Source:
Florida State University
Summary:
Scientists may be a step closer to understanding how life first emerged on Earth billions of years ago. Researchers have produced data supporting the idea that 10 amino acids believed to exist on Earth around 4 billion years ago were capable of forming foldable proteins in a high-salt (halophile) environment. Such proteins would have been capable of providing metabolic activity for the first living organisms to emerge on the planet between 3.5 and 3.9 billion years ago.

Dead Sea coastline. New research has yielded data supporting the idea that 10 amino acids believed to exist on Earth around 4 billion years ago were capable of forming foldable proteins in a high-salt (halophile) environment. Such proteins would have been capable of providing metabolic activity for the first living organisms to emerge on the planet between 3.5 and 3.9 billion years ago.
Credit: frag / Fotolia

A structural biologist at the Florida State University College of Medicine has made discoveries that could lead scientists a step closer to understanding how life first emerged on Earth billions of years ago.

Related Articles


Professor Michael Blaber and his team produced data supporting the idea that 10 amino acids believed to exist on Earth around 4 billion years ago were capable of forming foldable proteins in a high-salt (halophile) environment. Such proteins would have been capable of providing metabolic activity for the first living organisms to emerge on the planet between 3.5 and 3.9 billion years ago.

The results of Blaber's three-year study, which was built around investigative techniques that took more than 17 years to develop, are published in the journal Proceedings of the National Academy of Sciences.

The first living organisms would have been microscopic, cell-like organizations capable of replicating and adapting to environmental conditions -- a humble beginning to life on Earth.

"The current paradigm on the emergence of life is that RNA came first and in a high-temperature environment," Blaber said. "The data we are generating are much more in favor of a protein-first view in a halophile environment."

The widely accepted view among scientists is that RNA, found in all living cells, would have likely represented the first molecules of life, hypothesizing an "RNA-first" view of the origin of living systems from non-living molecules. Blaber's results indicate that the set of amino acids produced by simple chemical processes contains the requisite information to produce complex folded proteins, which supports an opposing "protein-first" view.

Another prevailing view holds that a high-temperature (thermophile) environment, such as deep-ocean thermal vents, may have been the breeding ground for the origin of life. "The halophile, or salt-loving, environment has typically been considered one that life adapted into, not started in," Blaber said. "Our study of the prebiotic amino acids and protein design and folding suggests the opposite."

Without the ability to fold, proteins would not be able to form the precise structures essential for functions that sustain life as we know it. Folding allows proteins to take on a globular shape through which they can interact with other proteins, perform specific chemical reactions, and adapt to enable organisms to exploit a given environment.

"There are numerous niches that life can evolve into," Blaber said. "For example, extremophiles are organisms that exist in high temperatures, high acidity, extreme cold, extreme pressure and extreme salt and so on. For life to exist in such environments it is essential that proteins are able to adapt in those conditions. In other words, they have to be able to fold."

Comet and meteorite fragments, like those that recently struck in the Urals region of Russia, have provided evidence regarding the arrival of amino acids on Earth. Such fragments predate Earth and would have been responsible for delivering a set of 10 prebiotic (before life) amino acids, whose origins are in the formation of our solar system.

Today the human body uses 20 common amino acids to make all its proteins. Ten of those emerged through biosynthetic pathways -- the way living systems evolve. Ten -- the prebiotic set -- can be made by chemical reactions without requiring any living system or biosynthetic pathway.

Scientific evidence exists to support many elements in theories of abiogenesis (the emergence of life), including the time frame (around 3.5 to 3.9 billion years ago) and the conditions on Earth and in its atmosphere at that time. Earth would have been made up of volcanic land masses (the beginning of the formation of continents), salty oceans and fresh-water ponds, along with a hot (around 80 degrees Celsius) and steamy atmosphere comprising carbon dioxide and nitrogen. Oxygen would have come later as a by-product of green plant life and bacteria that emerged.

Using a technique called top-down symmetric deconstruction, Blaber's lab has been able to identify small peptide building blocks capable of spontaneous assembly into specific and complex protein architectures. His recent work explored whether such building blocks can be composed of only the 10 prebiotic amino acids and still fold.

His team has achieved foldability in proteins down to 12 amino acids -- about 80 percent of the way to proving his hypothesis.

If Blaber's theory holds, scientists may refocus where they look for evidence in the quest to understand where, and how, life began.

"Rather than a curious niche that life evolved into, the halophile environment now may take center stage as the likely location for key aspects of abiogenesis," he said.

"Likewise, the role of the formation of proteins takes on additional importance in the earliest steps in the beginnings of life on Earth."


Story Source:

The above story is based on materials provided by Florida State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. L. M. Longo, J. Lee, M. Blaber. Simplified protein design biased for prebiotic amino acids yields a foldable, halophilic protein. Proceedings of the National Academy of Sciences, 2013; 110 (6): 2135 DOI: 10.1073/pnas.1219530110

Cite This Page:

Florida State University. "How life may have first emerged on Earth: Foldable proteins in a high-salt environment." ScienceDaily. ScienceDaily, 5 April 2013. <www.sciencedaily.com/releases/2013/04/130405064027.htm>.
Florida State University. (2013, April 5). How life may have first emerged on Earth: Foldable proteins in a high-salt environment. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2013/04/130405064027.htm
Florida State University. "How life may have first emerged on Earth: Foldable proteins in a high-salt environment." ScienceDaily. www.sciencedaily.com/releases/2013/04/130405064027.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Fossils & Ruins News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Ruins Thought To Be Port Actually Buried Greek City

Ruins Thought To Be Port Actually Buried Greek City

Newsy (Nov. 24, 2014) Media is calling it an "underwater Pompeii." Researchers have found ruins off the coast of Delos. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins