Snap-Fit Sugars:
A Recyclable Handle for Plug-and-Play Glycoscience
 

• Reliable bond orientation: A team led by Liming Zhang (UC Santa Barbara) and Peter Seeberger (MPIKG) has created a recyclable “handle” that precisely aligns sugar building blocks during glycan synthesis, solving a long-standing challenge in controlling bond orientation.
• Efficient and automation-friendly: The method works with a wide range of sugars, avoids high temperatures and exotic solvents, and is well suited for integration into automated processes.
• Advancing diagnostics and therapy: By enabling accurate control over structure and linkage, the approach could speed up the development of diagnostic tests, new drugs, and vaccines.

Glycan synthesis: how it works—and the challenge of bond orientation

Carbohydrate chemists join simple sugar building blocks into longer chains—glycans. These then serve as markers to detect diseases and as components of drugs and vaccines.  But only when precisely shaped: even small pattern changes affect the properties, and thus the results that glycans deliver.
In the lab, scientists use one sugar as the donor, which carries a small handle, and an acceptor with a chemical hook. The acceptor attaches to the donor after the donor has lost the handle, locking the two building blocks into a new glycan.
The catch is that this bond can take two orientations, and controlling it consistently across different sugar building blocks has proven a major challenge for glycoscience.

A built-in handle that steers the bond—and gets recycled

In a transatlantic collaboration, the laboratory teams directed by Liming Zhang at UC Santa Barbara and Peter Seeberger at the Max Planck Institute of Colloids and Interfaces discovered a key to this long-standing sugar puzzle.
The scientists added a handle to the donor sugar that guides the partner sugar into place, thus  steering the reaction to form the desired bond.

“It’s a ring-shaped piece that grips like a clamp:
it holds and aims the partner sugar so the two building blocks connect in the desired orientation,” explains Dr. Eric Sletten.

And that’s not all: once the glycan is formed, the handle pops off just as tidily as it guided the bond. Unlike conventional methods, about 60% of it can be recycled into a new handle, cutting costs and waste.

Automation-ready —for faster diagnostic and therapeutic tools

The UC/MPICI scientists tested the method on many different sugar building blocks—including particularly tricky ones—and observed mostly the desired orientations.
Just as important, the reactions were fast, did not require high temperatures ormexotic solvents, making the method well-suited to automated assembly.

“The team has developed a user-friendly approach that does not have to be adjusted for every coupling. This is another important step to bring automated glycan assembly closer to plug-and-play routines that are commonplace for synthesizing peptides and DNA,” concludes Prof. Seeberger.

This method makes it easier for scientists to adjust shape and linkage, and to study how glycan architecture affects their properties. Consequently, it promises to shorten the journey from idea to diagnostic tests and treatments.