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| RNA Molecule Has Big Implications For Life's Origins |
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| SciMed - Biology | |||
| TS-Si News Service | |||
| Sunday, 28 February 2010 16:00 | |||
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Boulder, CO, USA. A science team has created an extremely small RNA molecule that can catalyze a key reaction needed to synthesize proteins, the building blocks of life. The molecule is the smallest RNA enzyme ever known to perform a cellular chemical reaction. The new research builds on work by Tom Cech, a Nobel laureate and professor of chemistry and biochemistry at the University of Colorado at Boulder, and Professor Norman Pace of the CU molecular, cellular and developmental biology department (MCDB). They independently discovered that RNA can act as an enzyme, carrying out cellular-level chemical reactions. Because proteins are complex, one vexing question is where the first proteins came from. Tom Blumenthal, the MCDB chair says "It now appears that the first catalytic macromolecules could have been RNA molecules, since they are somewhat simpler, were likely to exist early in the formation of the first life forms, and are capable of catalyzing chemical reactions without proteins being present."
London, United Kingdom. New findings argue for the persistence of sex-linked chromosomes, such as the male Y  chromosome, refuting theories that the Y is doomed to extinction.
The results confirm that although these chromosom...London, UK. An animal model has been used to better understand the clinical significance of chronic psychotropic drug treatment on structural remodeling of the brain.
The effects of these structural changes has been unclear ...
Professor Michael Yarus of the MCDB at CU was the project lead on the new work. Rebecca Turk, a graduate student at was the lead author of a paper in the Proceedings of the National Academy of Sciences (PNAS) with Yarus and research associate Nataliya Chumachenko. In this paper the Michael Yarus group reports on the discovery that even an extremely tiny RNA can by itself catalyze a key reaction that would be needed to synthesize proteins. This is an unexpected finding since nobody expected an RNA molecule this small and simple to be able to do such a complicated thing. The finding adds weight to the RNA World Yarus noted that the RNA World hypothesis was complicated by the fact that RNA molecules are hard to make. "This work shows that RNA enzymes could have been far smaller, and therefore far easier to make under primitive conditions, than anyone has expected." If very simple RNA molecules such as the product of the Yarus lab could have accelerated chemical reactions in Earth's primordial stew, the chances are much greater that RNA could direct and accelerate biochemical reactions under primitive conditions. Before the advent of RNA, most biologists believe, there was a simpler world of chemical replicators that could only make more of themselves, given the raw materials of the time, Yarus said. "If there exists that kind of mini-catalyst, a 'sister' to the one we describe, the world of the replicators would also jump a long step closer and we could really feel we were closing in on the first things on Earth that could undergo Darwinian "In other words, we may have taken a substantial step toward the very origin of Earthly life," he said. "However, keep well in mind that the tiny replicator has not been found, and that its existence will be decided by experiments not yet done, perhaps not yet imagined." "Dr. Yarus has brought an innovative approach to bear on the key question of how complex processes originated," said Michael Bender, a biologist who oversees protein synthesis grants for the National Institute of General Medical Sciences at the National Institutes of Health (NIH). "By showing that a tiny segment of RNA can perform a key step of protein synthesis, this study has provided evidence that fundamental, protein-mediated cellular processes may have arisen from RNA-based mechanisms." CitationMichael Yarus' work is supported by a grant from the National Institutes of Health (NIH). In 2008 he was named a fellow of the American Association for the Advancement of Science (AAAS) for meritorious efforts to advance science or its applications.
CitationMultiple translational products from a five-
nucleotide ribozyme. Rebecca M. Turk, Nataliya V. Chumachenko, and Michael Yarus. Proceedings of the National Academy of Sciences 2010; ePub ahead of print. doi:10.1073/pnas.0912895107Download PDF Abstract An indispensable step in protein biosynthesis is the 2'(3') aminoacylation of tRNA by aminoacyl-tRNA synthetases. Here we show that a similar activity exists in a tiny, 5-nt-long RNA enzyme with a 3-nt active center. The small ribozyme initially trans-phenylalanylates a partially complementary 4-nt RNA selectively at its terminal 2'-ribose hydroxyl using PheAMP, the natural form for activated amino acid. The initial 2' Phe-RNA product can be elaborated into multiple peptidyl-RNAs. Reactions do not require divalent cations, and have limited dependence on monovalent cations. Small size and minimal requirements for regiospecific translational activity strongly support the hypothesis that minuscule RNA enzymes participated in early forms of translation. Keywords: aminoacyl-rna, enzyme, evolution, peptidyl-rna, rna.
 The TS-Si News Service is a collaborative effort by TS-Si.org editors, contributors, and corresponding institutions. Sources can include the cited individuals and organizations, as well as TS-Si.org staff contributions. Articles and news reports do not necessarily convey official positions of TS-Si, its partners, or affiliates. We welcome your comments. Use the form below to leave a public comment or send private correspondence via the TS-Si Contact Page. We will not divulge any personal details or place you on a mailing list without your permission.TS-Si is dedicated to the acceptance, medical treatment, and legal protection of individuals correcting the misalignment of their brains and their anatomical sex, while supporting their transition into society as hormonally reconstituted and surgically corrected citizens.
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