Featured Research

from universities, journals, and other organizations

Origins of life: In early Earth, iron helped RNA catalyze electron transfer

Date:
May 19, 2013
Source:
Georgia Institute of Technology, Research Communications
Summary:
A new study shows how complex biochemical transformations may have been possible under conditions that existed when life began on the early Earth. The study shows that RNA is capable of catalyzing electron transfer under conditions similar to those of the early Earth.

Georgia Tech School of Chemistry and Biochemistry postdoctoral fellow Chiaolong Hsiao (left) and professor Loren Williams examine on a light box a polyacrylamide gel surrounded by an iron solution to determine whether RNA is stable in the iron solution.
Credit: Georgia Tech Photo: Gary Meek

A new study shows how complex biochemical transformations may have been possible under conditions that existed when life began on the early Earth.

The study shows that RNA is capable of catalyzing electron transfer under conditions similar to those of the early Earth. Because electron transfer, the moving of an electron from one chemical species to another, is involved in many biological processes -- including photosynthesis, respiration and the reduction of RNA to DNA -- the study's findings suggest that complex biochemical transformations may have been possible when life began.

There is considerable evidence that the evolution of life passed through an early stage when RNA played a more central role, before DNA and coded proteins appeared. During that time, more than 3 billion years ago, the environment lacked oxygen but had an abundance of soluble iron.

"Our study shows that when RNA teams up with iron in an oxygen-free environment, RNA displays the powerful ability to catalyze single electron transfer, a process involved in the most sophisticated biochemistry, yet previously uncharacterized for RNA," said Loren Williams, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology.

The results of the study were scheduled to be published online on May 19, 2013, in the journal Nature Chemistry. The study was sponsored by the NASA Astrobiology Institute, which established the Center for Ribosomal Origins and Evolution (Ribo Evo) at Georgia Tech.

Free oxygen gas was almost nonexistent in Earth's atmosphere more than 3 billion years ago. When free oxygen began entering the environment as a product of photosynthesis, it turned Earth's iron to rust, forming massive banded iron formations that are still mined today. The free oxygen produced by advanced organisms caused iron to be toxic, even though it was -- and still is -- a requirement for life. Williams believes the environmental transition caused a slow shift from the use of iron to magnesium for RNA binding, folding and catalysis.

Williams and Georgia Tech School of Chemistry and Biochemistry postdoctoral fellow Chiaolong Hsiao used a standard peroxidase assay to detect electron transfer in solutions of RNA and either the iron ion, Fe2+, or magnesium ion, Mg2+. For 10 different types of RNA, the researchers observed catalysis of single electron transfer in the presence of iron and absence of oxygen. They found that two of the most abundant and ancient types of RNA, the 23S ribosomal RNA and transfer RNA, catalyzed electron transfer more efficiently than other types of RNA. However, none of the RNA and magnesium solutions catalyzed single electron transfer in the oxygen-free environment.

"Our findings suggest that the catalytic competence of RNA may have been greater in early Earth conditions than in present conditions, and our experiments may have revived a latent function of RNA," added Williams, who is also director of the RiboEvo Center.

This new study expands on research published in May 2012 in the journal PLoS ONE. In the previous work, Williams led a team that used experiments and numerical calculations to show that iron, in the absence of oxygen, could substitute for magnesium in RNA binding, folding and catalysis. The researchers found that RNA's shape and folding structure remained the same and its functional activity increased when magnesium was replaced by iron in an oxygen-free environment.

In future studies, the researchers plan to investigate whether other unique functions may have been conferred on RNA through interaction with a variety of metals available on the early Earth.

In addition to Williams and Hsiao, Georgia Tech School of Biology professors Roger Wartell and Stephen Harvey, and Georgia Tech School of Chemistry and Biochemistry professor Nicholas Hud, also contributed to this work as co-principal investigators in the Ribo Evo Center at Georgia Tech.

This work was supported by NASA (Award No. NNA09DA78A).


Story Source:

The above story is based on materials provided by Georgia Institute of Technology, Research Communications. The original article was written by Abby Robinson. Note: Materials may be edited for content and length.


Journal Reference:

  1. Chiaolong Hsiao, I-Chun Chou, C. Denise Okafor, Jessica C. Bowman, Eric B. O'Neill, Shreyas S. Athavale, Anton S. Petrov, Nicholas V. Hud, Roger M. Wartell, Stephen C. Harvey, Loren Dean Williams. RNA with iron(II) as a cofactor catalyses electron transfer. Nature Chemistry, 2013; DOI: 10.1038/nchem.1649

Cite This Page:

Georgia Institute of Technology, Research Communications. "Origins of life: In early Earth, iron helped RNA catalyze electron transfer." ScienceDaily. ScienceDaily, 19 May 2013. <www.sciencedaily.com/releases/2013/05/130519145653.htm>.
Georgia Institute of Technology, Research Communications. (2013, May 19). Origins of life: In early Earth, iron helped RNA catalyze electron transfer. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2013/05/130519145653.htm
Georgia Institute of Technology, Research Communications. "Origins of life: In early Earth, iron helped RNA catalyze electron transfer." ScienceDaily. www.sciencedaily.com/releases/2013/05/130519145653.htm (accessed September 1, 2014).

Share This




More Plants & Animals News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Washington Wildlife Center Goes Nuts Over Baby Squirrels

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Reuters - US Online Video (Aug. 30, 2014) An animal rescue in Washington state receives an influx of orphaned squirrels, keeping workers busy as they nurse them back to health. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Experimental Ebola Drug ZMapp Cures Lab Monkeys Of Disease

Experimental Ebola Drug ZMapp Cures Lab Monkeys Of Disease

Newsy (Aug. 29, 2014) In a new study, a promising experimental treatment for Ebola managed to cure a group of infected macaque monkeys. Video provided by Newsy
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
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:
from the past week

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