Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Metal Ions Regulate Terpenoid Metabolism in Insects

28.02.2013
Controlled by metal ions a prenyl synthase in leaf beetle larvae produces the precursors for chemical defenses or juvenile hormones.

Max Planck scientists in Jena, Germany, have discovered an unusual regulation of enzymes that catalyze chain elongation in an important secondary metabolism, the terpenoid pathway.


Larvae of horseradish leaf beetle Phaedon cochleariae

Photo: Sindy Frick / MPI for Chemical Ecology

In the horseradish leaf beetle Phaedon cochleariae a single enzyme can trigger the production of two completely different substances depending on whether it is regulated by cobalt, manganese or magnesium ions: iridoids, which are defensive substances the larvae use to repel predators, or juvenile hormones, which control insect’s development. Insects unlike plants do not have a large arsenal of the proteins called isoprenyl diphosphate synthases.

Therefore they may have developed another efficient option to channel metabolites into the different directions of terpenoid metabolism by using metal ions for control. (PNAS, Early Edition, February 25, 2013, DOI:10.1073/pnas.1221489110)

Natural products: 40,000 terpenes

Apart from the primary metabolism which produces substances that ensure the survival of the cells, there are additional biosynthetic pathways in all organisms. Their products may be less important for a single cell, but they can nevertheless be essential for the whole organism. These pathways are summarized as secondary metabolism. One of them is the terpenoid pathway: with more than 40,000 different known structures it generates one of the largest classes of natural products. Terpenoid molecules have diverse functions and can act as components in molecular signaling pathways, as toxins, fragrances or hormones.
The basic unit of all terpenes is a simple molecule containing five carbon atoms that can be joined to chains of different length. There are monoterpenes (C10 units, 2 x C5), sesquiterpenes (C15, 3 x C5), and even polymers, such as natural rubber, which comprises several hundred C5 units. Special enzymes mediate chain elongation. These enzymes have attracted the curiosity of scientists at the Max Planck Institute for Chemical Ecology, Jena, and the Leibniz Institute for Plant Biochemistry in Halle. They studied mechanistic alternatives of how chain elongation is regulated.

Metal ions instead of specialized enzymes
Enzymes involved in chain elongation belong to the group of isoprenyl diphosphate synthases. Such an enzyme was isolated from larvae of the horseradish leaf beetle Phaedon cochleariae. It raised the interest of Antje Burse, project group leader in the Department of Bioorganic Chemistry at the Max Planck Institute for Chemical Ecology.

Experiments with larvae in which the enzyme encoding gene was silenced showed that the protein was involved in the formation of the C10 monoterpene chrysomelidial that larvae produce to defend themselves against predators. The larvae accumulate this monoterpene in special glands and release it as a defensive secretion when they are attacked by their enemies, such as ants.

However, surprising results emerged after comprehensive biochemical characterization of the enzyme. “After we had conducted an in vitro analysis of the protein, including measurements of product formation in the presence of different metal ions as co-factors, we were surprised to discover that only geranyl diphosphate (C10), a precursor for the defensive substance chrysomelidial, was produced after addition of cobalt and manganese ions. On the other hand, adding magnesium ions resulted in the formation of farnesyl diphosphate (C15), a potential precursor for juvenile hormones, which is 5 carbon atoms longer,” says the scientist. All three metals were found in larval tissue, leading to the assumption that enzyme catalysis is directed by the different metal co-factors in the larvae, whichever is predominant in amount: Towards toxin or hormone − physiologically a major difference.

Sequence comparisons cannot replace a thorough biochemical analysis

How the different metal ions modify the product range of the enzyme is still unclear. It is very likely that the varying atomic radii of the metal ions involved in the catalysis effect changes in the spatial structure of the enzyme, which prevent or allow the admission of a third C5 unit and hence result in the production of C10 or C15 molecules.

“Our experiments provide two important findings,” says Wilhelm Boland, director at the Max Planck Institute. “First, the directing influence of metal ions on the product formation of isoprenyl diphosphate synthases is a novel “control element” in the regulation of the terpene metabolism which should be included in future experimental settings. And secondly: The diversity of terpenoid molecules cannot be attributed solely to the broad substrate specificity of some enzymes in the last steps of the metabolic pathway, but is in fact already inherent in early biosynthetic steps.” Nature continues to provide interesting answers to the question how organisms manage to produce tens of thousands of different secondary metabolites. [JWK/AO]

Original Publication:

Sindy Frick, Raimund Nagel, Axel Schmidt, René R. Bodemann, Peter Rahfeld, Gerhard Pauls, Wolfgang Brandt Jonathan Gershenzon, Wilhelm Boland, Antje Burse: Metal ions control product specificity of isoprenyl diphosphate synthases in the insect terpenoid pathway. Proceedings of the National Academy of Sciences USA, Early Edition, February 25, 2013, DOI:10.1073/pnas.1221489110

http://dx.doi.org/10.1073/pnas.1221489110

Further Information:
Dr. Antje Burse, +49 3641 57-1265, aburse@ice.mpg.de
Picture Requests:
Angela Overmeyer M.A., +49 3641 57-2110, overmeyer@ice.mpg.de
or Download via http://www.ice.mpg.de/ext/735.html

Dr. Jan-Wolfhard Kellmann | Max-Planck-Institut
Further information:
http://www.ice.mpg.de/ext/515.html

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>