In today's world of sophisticated organisms proteins are the stars. They are the indispensible catalytic workhorses, carrying out the processes essential to life. But long, long ago ribonucleic acid (RNA) reigned supreme.
Now Northwestern University researchers have produced an atomic picture that shows how two of these very old molecules interact with each other. It is a rare glimpse of the transition from an ancient, RNA-based world to our present, protein-catalyst dominated world.
The scientists are the first to show the atomic details of how ribonuclease P (RNase P) recognizes, binds and cleaves transfer RNA (tRNA). They used the powerful X-rays produced by the Advanced Photon Source at Argonne National Laboratory to obtain images from crystals formed by these two RNA molecules. The result is a snapshot of one of the most complex models of a catalytic RNA and its target.
Details of the structure will be published Nov. 14 by the journal Nature.
"RNA is an ancient molecule, but it is pretty sophisticated," said Alfonso Mondragón, professor of molecular biosciences in the Weinberg College of Arts and Sciences. He led the research. "Our crystal structure shows that it has many of the properties we ascribe to modern molecules. RNA is a catalyst that has much of the versatility and complexity of modern-day proteins."
For billions of years and still to this day, the function of RNase P -- found in nearly all organisms, from bacteria to humans -- has been to cleave transfer tRNA. If the tRNA is not cleaved, it is not useful to the cell.
"We knew this important chemistry happened, that RNA acts as a catalyst, but we didn't know exactly how until now," Mondragón said. "We now have a better understanding of how RNA works."
RNase P is formed by a large RNA core plus a small protein, illustrating the evolutionary shift from an RNA world toward a protein-dominated world. The protein helps recognize the tRNA, but most of the recognition occurs through RNA-RNA interactions involving shape complementarity and also base pairing.
The structure shows that once RNase P recognizes tRNA, it docks and, assisted by metal ions, cuts one chemical bond. This matures the tRNA, producing a smaller RNA molecule that now can contribute to fundamental processes in the cell. The RNA-based enzyme does this over and over, cutting each tRNA in exactly the same place every time.
"The discovery nearly 30 years ago that RNA molecules can have a catalytic function raised the idea that maybe RNA was the first molecule," Mondragón said. "Our work reinforces this notion of the existence of an RNA world when life first began."
The title of the Nature paper is "Structure of a bacterial ribonuclease P holoenzyme in complex with tRNA." In addition to Mondragón, other authors of the paper are Nicholas J. Reiter, Amy Osterman, Alfredo Torres-Larios and Kerren K. Swinger, of Northwestern, and Tao Pan, of the University of Chicago.
Megan Fellman | EurekAlert!
MicroRNA helps cancer evade immune system
19.09.2017 | Salk Institute
Ruby: Jacobs University scientists are collaborating in the development of a new type of chocolate
18.09.2017 | Jacobs University Bremen gGmbH
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
19.09.2017 | Event News
19.09.2017 | Physics and Astronomy
19.09.2017 | Power and Electrical Engineering