13 March 2015

Copenhagen chemists discover an unlikely connection

Physical chemistry As with magnets and alternating current, positively charged molecules never aim for one another. Indeed, similarly charged atoms are repelled. Nevertheless, a team from the University of Copenhagen’s Department of Chemistry has managed to become the first to bond positively charged phosphorus atoms with positively charged hydrogen ones. Their insight may prove pivotal to understanding how biologically important molecules such as DNA and proteins form properly.

Top research

Anne Hansen, Lin Du and Henrik Kjærgaard of the physical chemistry section have published their discovery in the Journal of Physical Chemistry Letters.

Discovery could give fresh insight into how proteins are shaped

Function follows form where proteins are concerned. Whether they serve as signaling agents, catalysts or biological building blocks, proteins are only effective if their molecular structure is spot on. Their composition is largely dependent on hydrogen atoms in the molecules, and the ability of these to create hydrogen bonds with other elements.

Atomic charges not what was thought, study suggests

Previously, researchers assumed that positively charged hydrogen could only create hydrogen bonds with negatively charged elements like oxygen, fluorine and nitrogen. That positive hydrogen can also be bound to positive phosphorus opens up a world of fresh insight into biological processes. It also provides the basis for an entirely new understanding of how atomic charge works. Thus, it may come as no small surprise that Professor Henrik Kjærgaard is proud of their discovery.

“It was thought that atomic charge was global, that is, as something that was uniform and spherically shaped. But our experiment demonstrates, as clear as day, that charge is asymmetric – that small areas of negative charge exist upon atoms which are in fact positive,” explains Kjærgaard.

Combination lab behind breakthrough

The discovery was worked on in Professor Kjærgaard’s Quantum, Spectra and Dynamics group. The group specializes in combining spectroscopic analyses with theoretical modelling and computational chemistry