Göttingen scientists use BESSY II to decode basic mechanism underlying biochemical reactions

Structure of the sugar molecule bound by the enzyme transketolase immediately prior to its being split

Enzymes are life’s molecular catalysts and figure prominently in cellular metabolism. It has been speculated that in the course of a biochemical reaction enzymes physically bend their substrates to split them. Now for the first time ever, scientists at the Göttingen Center for Molecular Biosciences (GZMB) have successfully used BESSY II's MX beamline to unequivocally confirm this hypothesis. The results from this study have been published in the renowned scientific journal Nature Chemistry.

The Göttingen team around Prof. Dr. Kai Tittmann and Prof. Dr. Ralf Ficner started out by growing high order protein crystals of the human enzyme transketolase, which plays a central role in human metabolism during sugar processing. Natural sugar substrates were added to the protein crystals. Analysis of the enzyme’s crystalline structure was subsequently performed at electron storage ring BESSY II's MX beamline and in French Grenoble. The scientists were able to determine the structure of the sugar molecule bound by the enzyme immediately prior to its being split in half at an ultrahigh spatial resolution of 0.1 nanometers. “The snapshot we got of an enzyme at work, which really is unprecedented in terms of resolution, unequivocally reveals how the sugar substrate is being bent by the enzyme, similar to a vise clamping a work piece,” Prof. Tittmann explains.

In many cases, enzymes are drug targets. Which is why these new insights are important for the development of customized, highly specific active substances like those used in cancer therapy. “Even the human transketolase used in this study plays a key role in cancer cell metabolism,” says Prof. Tittmann.

Source: Göttingen University