A pretzel is a type of baked bread product made from dough most commonly shaped into a twisted knot. A group of researchers at the University Of Amsterdam discovered a new class of Pretzel-like molecule during their own synthesizing procedure of Lasso Peptide. Lasso peptide is a highly compact and stable organic molecule which is potential for producing the medicine.
As per the study, synthesizing a Lasso Peptide is very complex because of its complex structure and no one can able to synthesize it yet. However, this five-year research effort of Prof. Jan van Maarseveen and his team could pave the way for the synthesis of so-called lasso peptides. They shared all the study paper regarding this breakthrough discovery in The Nature Communication.
According to researchers, this newly discovered molecule consisting of two molecular rings oppositely coupled at a central carbon atom, very similar to the pretzel loop. In addition, Lasso peptide are small proteins consist of a molecular 'loop' around a molecular 'rope'. They were first isolated from the bacteria at the turn of the current century.
However, the latest DNA result suggests that lasso peptides are quite common in the realm of bacteria. Their biological function is working similarly as an antibiotic against other micro-organisms, which makes them a potential new class of antibiotics. But after 15 years of discovery, synthetic chemists have not yet been able to develop a strategy due to their unique and complex molecular architecture.
Regarding this researcher emphasized that the molecular rope in this Pretzel-like molecule is usually tightly bound within the molecular loop. It's the main obstacle to finding a proper synthesizing strategy. Last year, Scottish chemist Sir Fraser Stoddart was able to distinguish lasso peptide with another mechanically-interlocked molecular architecture called Rotaxane. That's why he received the Nobel Prize for this breakthrough work.
He explained that the molecular rope of Rotaxane can easily 'pull' through the loop during the synthesis. However, for Lasso Peptide it's impossible and therefore the researcher of the University of Amsterdam discovers a distinct synthetic route where they force the loop to close in the right place around the rope. During a demonstration, they eventually managed to create a molecular scaffold assisting the synthesis in such a way that the loop correctly forms around the rope.
This alternative synthesis method is a major step forward in the synthetic route towards functional lasso peptides. Regarding this, Luuk Stemers, a Ph.D. scholar demonstrates the effectiveness of this method. In this process, he managed to create a molecular scaffold assisting the synthesis in such a way that the loop correctly forms around the rope.
Additionally, researchers named these new Pretzel-like molecules as quasi  catenanes. While actual Catenanes consist of two loosely intertwined molecular ring-like structures. Catenanes first discovered by the French chemist Jean-Pierre Sauvage and received Nobel Prize for this. In fact, this new synthesizing procedure provides an easy way to break the strong bond of the quasi  catenanes which will unlock the ring for further study.