Navigation Links
Metabolism may have started in our early oceans before the origin of life
Date:4/25/2014

The chemical reactions behind the formation of common metabolites in modern organisms could have formed spontaneously in the earth's early oceans, questioning the events thought to have led to the origin of life.

In new research funded by the Wellcome Trust, researchers at the University of Cambridge reconstructed the chemical make-up of the earth's earliest ocean in the laboratory. The team found the spontaneous occurrence of reaction sequences which in modern organisms enable the formation of molecules essential for the synthesis of metabolites such as amino acids, nucleic acids and lipids. These organic molecules are critical for the cellular metabolism seen in all living organisms.

The detection of one of the metabolites, ribose 5-phosphate, in the reaction mixtures is particularly noteworthy, as RNA precursors like this could in theory give rise to RNA molecules that encode information, catalyze chemical reactions and replicate.

It was previously assumed that the complex metabolic reaction sequences, known as metabolic pathways, occurring in modern cells were only possible due to the presence of enzymes. Enzymes are highly complex molecular machines that are thought to have come into existence during the evolution of modern organisms. However, the team's reconstruction reveals that metabolism-like reactions could have occurred naturally in our early oceans, before the first organisms evolved.

Almost 4 billion years ago life on Earth began in iron-rich oceans that dominated the surface of the planet. This was an oxygen-free world, pre-dating photosynthesis, when the redox state of iron was different and much more soluble to act as potential catalysts. In the Archean sea, iron, other metals and phosphate, facilitated a series of reactions which resemble the core of cellular metabolism occurring in the absence of enzymes.

The findings suggests that metabolism predates the origin of life and evolved through the chemical conditions that prevailed in the worlds earliest oceans.

"Our results show that reaction sequences that resemble two essential reaction cascades of metabolism, glycolysis and the pentose-phosphate pathways, could have occurred spontaneously in the earth's ancient oceans," says Dr. Markus Ralser at the Department of Biochemistry at the University of Cambridge and the National Institute for Medical Research, who led the study.

"In our reconstructed version of the ancient Archean ocean, these metabolic reactions were particularly sensitive to the presence of ferrous iron which was abundant in the early oceans, and accelerated many of the chemical reactions that we observe. We were surprised by how specific these reactions were" he added.

The conditions of the prebiotic sea were reconstructed based on the composition of various early sediments described in the scientific literature which identify soluble forms of iron as one of the most frequent molecules in the prebiotic oceans.

Alexandra V Turchyn from the Department of Earth Sciences at the University of Cambridge, one of the co-authors of the study said: "We are quite certain that the earliest oceans contained no oxygen, and so any iron present would have been soluble in these oxygen-devoid oceans. It's therefore possible that concentrations of iron could have been quite high".

The different metabolites were incubated at temperatures of 50-90˚C, similar to what might be expected close to the hydrothermal vents of an oceanic volcano, and would not support the activity of conventional protein enzymes. The chemical products were separated and analyzed by liquid chromatography tandem mass spectrometry.

Some of the observed reactions could also take place in water but were accelerated by the presence of metals that served as catalysts. "In the presence of iron and other compounds found in the oceanic sediments, 29 metabolism-like chemical reactions were observed, including those that produce some of the essential chemicals of metabolism, for example precursors to the building blocks of proteins or RNA," says Ralser.

"These results indicate that the basic architecture of the modern metabolic network could have originated from the chemical and physical constraints that existed on the prebiotic Earth."

How the first enzymes adopted the metal-catalyzed reactions described by the scientists remains to be established.


'/>"/>
Contact: Meera Senthilingam
m.senthilingam@wellcome.ac.uk
020-761-17329
Wellcome Trust
Source:Eurekalert

Related biology news :

1. UAlberta researchers examine metabolism in defective cells
2. Hot on the trail of cellular metabolism
3. Effects of meth use on brain metabolism, sleep studied
4. Targeting metabolism to develop new prostate cancer treatments
5. Could metabolism play a role in epilepsy?
6. FASEB announces 2014 Science Research Conference: Folic Acid, Vitamin B12 and One Carbon Metabolism
7. FASEB announces 2014 SRC: Phospholipid Cell Signaling & Metabolism in Inflammation & Cancer
8. FASEB announces SRC: Molecular Mechanisms of Intestinal Lipid Transport & Metabolism
9. How metabolism and brain activity are linked
10. Nutrition influences metabolism through circadian rhythms, UCI study finds
11. SIRT5 regulation has dramatic effect on mitochondrial metabolism
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/22/2016)... Jan. 22, 2016 ... of the "Global Biometrics Market in ... offering. --> http://www.researchandmarkets.com/research/p74whf/global_biometrics ) ... "Global Biometrics Market in Retail Sector 2016-2020" ... --> Research and Markets ( http://www.researchandmarkets.com/research/p74whf/global_biometrics ...
(Date:1/20/2016)...   MedNet Solutions , an innovative SaaS-based eClinical ... research, is pleased to announce the attainment of record-setting ... result of the company,s laser focus on (and growing ... it,s comprehensive, easy-to-use and highly affordable cloud-based technology platform. ... MedNet growth achievements in 2015 include: , ...
(Date:1/15/2016)... 15, 2016 Recent publicized breaches in cyber ... new ways to ensure data security and user authentication ... and Android that ties a user,s mobile ... into a hardware authorization token. Customer service agents who ... on their KodeKey enabled device to verify their identity. ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... Feb. 11, 2016  Vermillion, Inc. (NASDAQ: VRML ... today announced the formation of the Steering Committee for ... --> Pelvic masses can present physicians ... management. Once pregnancy is ruled out, pelvic masses may ... advanced endometriosis, benign ovarian tumors and gastrointestinal and urinary ...
(Date:2/11/2016)... 2016  Wellcentive today announced it has been ... -based community care organization (CCO) with more ... quality reporting and care management solutions and services. ... of quality managers, analysts and care managers while ... serving FamilyCare members. Oregon ...
(Date:2/11/2016)... 2016   BioInformant announces the February 2016 ... Products, Opportunities, Tools, and Technologies – Market Size, Segments, ... The first and only ... industry, BioInformant has more than a decade of historical ... by stem cell type. This powerful 175 page global ...
(Date:2/10/2016)... Febr. 10, 2016 /PRNewswire/ - BioAmber Inc. (NYSE: BIOA ... announce that Mitsui & Co. Ltd., its partner in ... plant, is investing an additional CDN$25 million in the ... stake from 30% to 40%.  Mitsui will also play ... produced in Sarnia , providing dedicated ...
Breaking Biology Technology: