(Press-News.org) 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 the Earth's atmosphere more than 3 billion years ago. When free oxygen began entering the environment as a product of photosynthesis, it turned the 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.
INFORMATION:
This work was supported by NASA (Award No. NNA09DA78A). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of NASA.
RNA capable of catalyzing electron transfer on early earth with iron's help, study says
2013-05-20
ELSE PRESS RELEASES FROM THIS DATE:
Computational tool translates complex data into simplified 2-dimensional images
2013-05-20
NEW YORK, NY (May 19, 2013) — In their quest to learn more about the variability of cells between and within tissues, biomedical scientists have devised tools capable of simultaneously measuring dozens of characteristics of individual cells. These technologies have led to new challenges, however, as scientists now struggle with how to make sense of the resulting trove of data. Now a solution may be at hand. Researchers at Columbia University and Stanford University have developed a computational method that enables scientists to visualize and interpret "high-dimensional" ...
Sea level influenced tropical climate during the last ice age
2013-05-20
Scientists look at past climates to learn about climate change and the ability to simulate it with computer models. One region that has received a great deal of attention is the Indo-Pacific warm pool, the vast pool of warm water stretching along the equator from Africa to the western Pacific Ocean.
In a new study, Pedro DiNezio of the International Pacific Research Center, University of Hawaii at Manoa, and Jessica Tierney of Woods Hole Oceanographic Institution investigated preserved geological clues (called "proxies") of rainfall patterns during the last ice age when ...
Archaeological genetics: It's not all as old as it at first seems
2013-05-20
Genomic analyses suggest that patterns of genetic diversity which indicate population movement may not be as ancient as previously believed, but may be attributable to recent events. This study published in BioMed Central's open access journal Investigative Genetics, based in the Netherlands, is able to genetically characterize geographically separated subpopulations within the country and map them to population movement within the last 2000 years.
Looking at more than 400,000 SNPs (genetic variations) of almost 1000 people across the Netherlands, this study found that ...
Heat-related deaths in Manhattan projected to rise
2013-05-20
Residents of Manhattan will not just sweat harder from rising temperatures in the future, says a new study; many may die. Researchers say deaths linked to warming climate may rise some 20 percent by the 2020s, and, in some worst-case scenarios, 90 percent or more by the 2080s. Higher winter temperatures may partially offset heat-related deaths by cutting cold-related mortality—but even so, annual net temperature-related deaths might go up a third. The study, published this week in the journal Nature Climate Change, was done by a team at Columbia University's Earth Institute ...
New theory on genesis of osteoarthritis comes with successful therapy in mice
2013-05-20
Scientists at Johns Hopkins have turned their view of osteoarthritis (OA) inside out. Literally. Instead of seeing the painful degenerative disease as a problem primarily of the cartilage that cushions joints, they now have evidence that the bone underneath the cartilage is also a key player and exacerbates the damage. In a proof-of-concept experiment, they found that blocking the action of a critical bone regulation protein in mice halts progression of the disease.
The prevailing theory on the development of OA focuses on joint cartilage, suggesting that unstable mechanical ...
Scientists explore roots of future tropical rainfall
2013-05-20
How will rainfall patterns across the tropical Indian and Pacific regions change in a future warming world? Climate models generally suggest that the tropics as a whole will get wetter, but the models don't always agree on where rainfall patterns will shift in particular regions within the tropics.
A new study, published online May 19 in the journal Nature Geoscience, looks to the past to learn about the future of tropical climate change, and our ability to simulate it with numerical models.
Pedro DiNezio of the University of Hawaii and Jessica Tierney of Woods Hole ...
Kinks and curves at the nanoscale
2013-05-20
One of the basic principles of nanotechnology is that when you make things extremely small—one nanometer is about five atoms wide, 100,000 times smaller than the diameter of a human hair—they are going to become more perfect.
"Perfect in the sense that their arrangement of atoms in the real world will become more like an idealized model," says University of Vermont engineer Frederic Sansoz, "with smaller crystals—in for example, gold or copper—it's easier to have fewer defects in them."
And eliminating the defects at the interface separating two crystals, or grains, ...
Whole-cell vaccine was more effective than acellular vaccine during CA pertussis outbreak
2013-05-20
OAKLAND, Calif., May 20, 2013 — Whole-cell pertussis vaccines were more effective at protecting against pertussis than acellular pertussis vaccines during a large recent outbreak, according to a new Kaiser Permanente study published in Pediatrics.
Whole-cell pertussis vaccines, also called DTwP, were available from the 1940s to 1990s, but were associated with safety concerns that ultimately led to the development of acellular pertussis vaccines, which are also called DTaP. By the late 1990s, the United States had switched from whole-cell to acellular vaccines for all ...
Blame your parents for bunion woes
2013-05-20
A novel study reports that white men and women of European descent inherit common foot disorders, such as bunions (hallux valgus) and lesser toe deformities, including hammer or claw toe. Findings from the Framingham Foot Study—the first to estimate the heritability of foot disorders in humans—appear in Arthritis Care & Research, a journal published by Wiley on behalf of the American College of Rheumatology (ACR).
Previous studies show that as many as 60% of older adults have foot disorders which may limit mobility and reduce their quality of life. In fact, bunions affect ...
Genetic diversity within tumors predicts outcome in head and neck cancer
2013-05-20
A new measure of the heterogeneity – the variety of genetic mutations – of cells within a tumor appears to predict treatment outcomes of patients with the most common type of head and neck cancer. In the May 20 issue of the journal Cancer, investigators at Massachusetts General Hospital (MGH) and Massachusetts Eye and Ear Infirmary describe how their measure was a better predictor of survival than most traditional risk factors in a small group of patients with squamous cell carcinoma of the head and neck.
"Our findings will eventually allow better matching of treatments ...