Scientists at the University of Basel, ETH Zurich, and NCCR Molecular Systems Engineering have developed an artificial metalloenzyme that catalyses a reaction inside of cells without equivalent in nature. This could be a prime example for creating new non-natural metabolic pathways inside living cells, as reported today in Nature.
The artificial metalloenzyme, termed biot-Ru–SAV, was created using the biotin–streptavidin technology. This method relies on the high affinity of the protein streptavidin for the vitamin biotin, where compounds bound to biotin can be introduced into the protein to generate artificial enzymes.
In this study the authors introduced an organometallic compound, with the metal ruthenium at its base. Organometallic compounds are molecules containing at least one bond between a metal and a carbon atom, and are often used as catalysts in industrial chemical reactions. However, organometallic catalysts perform poorly, if at all, in aqueous solutions or cellular-like environments, and need to be incorporated into protein scaffolds like streptavidin to overcome these limitations.
“The goal was to create an artificial metalloenzyme that can catalyse olefin metathesis, a reaction mechanism that is not present among natural enzymes,” says Thomas R Ward, Professor at the Department of Chemistry, University of Basel, and senior author of the study. The olefin metathesis reaction is a method for the formation and redistribution of carbon-carbon double bonds widely used in laboratory research and large-scale industrial productions of various chemical products. Biot-Ru–SAV catalyses a ring-closing metathesis to produce a fluorescent molecule for easy detection and quantification.
Periplasm as reaction compartment
However, the environment inside a living cell is far from ideal for the proper functioning of organometallic-based enzymes. “The main breakthrough was the idea to use the periplasm of Escherichia coli as a reaction compartment, whose environment is much better suited for an olefin metathesis catalyst,” says Markus Jeschek, a researcher from the team of co-supervising author Sven Panke at the Department of Biosystems Science and Engineering, ETH Zurich in Basel. The periplasm, the space between the inner cytoplasmic membrane and the bacterial outer membrane in gram-negative bacteria, contains low concentrations of metalloenzymes inhibitors, such as glutathione.
Having found ideal in vivo conditions, the authors went a step forward and decided to optimize biot-Ru–SAV by applying principles of directed evolution, a method that mimics the process of natural selection to evolve proteins with enhanced properties or activities. “We could then develop a simple and robust screening method that allowed us to test thousands of biot-Ru–SAV mutants and identify the most active variant,” Ward explains.
Not only could the authors markedly improve the catalytic properties of biot-Ru–SAV, but they could also show that organometallic-based enzymes can be engineered and optimized for different substrates, thus producing a variety of different chemical products. “The exciting thing about this is that artificial metalloenzymes like biot-Ru–SAV can be used to produce novel high added-value chemicals,” Ward says. “It has a lot of potential to combine both chemical and biological tools to ultimately utilize cells as molecular factories.”
Markus Jeschek, Raphael Reuter, Tillmann Heinisch, Christian Trindler, Juliane Klehr, Sven Panke & Thomas R. Ward
Directed evolution of artificial metalloenzymes for in vivo metathesis
Nature (2016), doi: 10.1038/nature19114
• Prof. Thomas R. Ward, University of Basel, Department of Chemistry, Tel. +41 61 267 10 04, email: firstname.lastname@example.org
• Prof. Sven Panke, ETH Zurich, Department of Biosystems Science and Engineering, Tel. +41 61 387 32 09, email: email@example.com
Reto Caluori | Universität Basel
Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard
New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences