Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Larger Pocket

12.08.2014

 

Reprogramed nonribosomal peptide synthetase incorporates amino acids with reactive sites for “click” chemistry

A single targeted mutation is enough to alter a natural peptide system so that it also incorporates non-natural amino acids into peptides, report Swiss scientists in the journal Angewandte Chemie.

The mutation increases the size of the binding cavity in one domain of the system, which changes the substrate specificity. The researchers are thus able to incorporate amino acids with a specific reactive group that can later be used to easily modify the peptide.

In the search for new pharmaceuticals through the use of combinatorial chemistry and screening processes, researchers are often faced with the task of modifying and varying natural substances—sometimes by adding further molecular components, for example.

Highly specific coupling with molecular markers is particularly important because it allows scientists to monitor the distribution of natural substances in cells and tissues. Coupling reactions that are almost as snapping components together can be carried out by a technique known as “click chemistry”. This method encompasses broadly applicable reactions like those between alkynes and azides, which deliver high yields.

For this technique, the natural substance must first be equipped with such an alkyne or azide group. One way to achieve this would be through the incorporation of amino acids with alkyne or azide side chains into proteins through alteration of their biosynthesis.

However, many interesting natural substances, such as the gramicidin antibiotics, are not formed by way of the classical pathways of protein biosynthesis through the reading of genes and the assembly of amino acids in the ribosomes. Instead, they are made by nonribosomal peptide synthetases, very large multi-enzyme complexes whose individual modules hang together like pearls on a necklace.

These activate the amino acid building blocks and incorporate them into the growing peptide chain. The number, type, and ordering of the individual modules determine the length and composition of the resulting—usually short-chained—peptide. In addition to the usual amino acids, it is also possible to incorporate other, sometimes unusual, individual building blocks, which allows for the formation of an astonishingly large variety of peptides.

Researchers working with Donald Hilvert at the ETH in Zurich exchanged an individual amino acid in one module of the nonribosomal production apparatus for the antibiotic gramicidin S through a mutation. This altered an area known as an A domain, which specifically recognizes and activates the natural amino acid phenylalanine.

The mutation causes the binding cavity to be roomier, so that non-natural amino acids that contain an azide or alkyne group can be activated and incorporated into the peptide chain in place of phenylalanine. The catalytic activity of the overall system is not affected by this change in selectivity.

Because many different nonribosomal synthesis systems contain such A domains, this new method is potentially a general approach for equipping important natural substances with a reactive site for highly specific covalent modification.

About the Author

Dr. Donald Hilvert is Professor of Chemistry at the ETH Zürich. His research group is investigating how enzymes work and evolve and applying this knowledge to the design of new protein-based catalysts. These efforts have been recognized by a number of awards, including the Pfizer Award in Enzyme Chemistry and the Emil Thomas Kaiser Award from the Protein Society.

Author: Donald Hilvert, ETH Zürich (Switzerland), http://www.protein.ethz.ch

Title: Reprogramming Nonribosomal Peptide Synthetases for "Clickable" Amino Acids

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201405281

Donald Hilvert | Angewandte Chemie - Wiley
Further information:
http://pressroom.angewandte.org

Further reports about: ETH Pocket acid acids alkyne amino phenylalanine reactions reactive substances technique

More articles from Life Sciences:

nachricht Rice University lab runs crowd-sourced competition to create 'big data' diagnostic tools
30.06.2016 | Rice University

nachricht A protein coat helps chromosomes keep their distance
30.06.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Thousands on one chip: New Method to study Proteins

Since the completion of the human genome an important goal has been to elucidate the function of the now known proteins: a new molecular method enables the investigation of the function for thousands of proteins in parallel. Applying this new method, an international team of researchers with leading participation of the Technical University of Munich (TUM) was able to identify hundreds of previously unknown interactions among proteins.

The human genome and those of most common crops have been decoded for many years. Soon it will be possible to sequence your personal genome for less than 1000...

Im Focus: Optical lenses, hardly larger than a human hair

3D printing enables the smalles complex micro-objectives

3D printing revolutionized the manufacturing of complex shapes in the last few years. Using additive depositing of materials, where individual dots or lines...

Im Focus: Flexible OLED applications arrive

R2D2, a joint project to analyze and development high-TRL processes and technologies for manufacture of flexible organic light-emitting diodes (OLEDs) funded by the German Federal Ministry of Education and Research (BMBF) has been successfully completed.

In contrast to point light sources like LEDs made of inorganic semiconductor crystals, organic light-emitting diodes (OLEDs) are light-emitting surfaces. Their...

Im Focus: Unexpected flexibility found in odorant molecules

High resolution rotational spectroscopy reveals an unprecedented number of conformations of an odorant molecule – a new world record!

In a recent publication in the journal Physical Chemistry Chemical Physics, researchers from the Max Planck Institute for the Structure and Dynamics of Matter...

Im Focus: 3-D printing produces cartilage from strands of bioink

Strands of cow cartilage substitute for ink in a 3D bioprinting process that may one day create cartilage patches for worn out joints, according to a team of engineers. "Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches," said Ibrahim T. Ozbolat, associate professor of engineering science and mechanics. "Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this."

Cartilage is a good tissue to target for scale-up bioprinting because it is made up of only one cell type and has no blood vessels within the tissue. It is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Quantum technologies to revolutionise 21st century - Nobel Laureates discuss at Lindau

30.06.2016 | Event News

International Conference ‘GEO BON’ Wants to Close Knowledge Gaps in Global Biodiversity

28.06.2016 | Event News

ERES 2016: The largest conference in the European real estate industry

09.06.2016 | Event News

 
Latest News

Modeling NAFLD with human pluripotent stem cell derived immature hepatocyte like cells

30.06.2016 | Health and Medicine

Rice University lab runs crowd-sourced competition to create 'big data' diagnostic tools

30.06.2016 | Life Sciences

A drop of water as a model for the interplay of adhesion and stiction

30.06.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>