In recognition of their groundbreaking work on the elucidation of the three-dimensional structure of the protein envelope of viruses, Professors Stephen C. Harrison (Harvard University, Cambridge/USA) and Michael G. Rossmann (Purdue University, West Lafayette/USA) are awarded the Paul Ehrlich and Ludwig Darmstaedter Prize 2001, endowed with 120,000 DM. The prize is awarded annually on Paul Ehrlich's birthday, 14 March, in the Paulskirche in Frankfurt. Their discoveries underline the importance of highly qualified basic research.

The genetic material of virus particles is surrounded by an envelope consisting of symmetrically arranged protein building blocks. It has been known since the 1930s that viral envelope proteins can crystallise. With the help of X-ray structure analysis, it is possible to obtain more precise information on the three-dimensional shape of a crystallised protein. Since the protein envelopes of virus particles are very large and consist of several proteins, deciphering their three-dimensional structure was a great challenge. Harrison and Rossmann succeeded in this for the first time in 1978 and 1979 by developing new crystallographic techniques and exploiting the internal symmetry of the virus particles. Because of the easy availability of larger quantities, the scientists chose two plant viruses as the object of investigation: Harrison clarified the structure of the Tomato Bushy Stunt Virus and Rossmann the structure of the Southern Bean Mosaic Virus. This was followed by the characterisation of a whole number of viruses that are responsible for diseases in humans and animals. Examples include the common cold viruses (Rossmann) and the tumour-causing polyomaviruses (Harrison). Since then, the field of virus crystallography has expanded rapidly.

Understanding the three-dimensional structures of proteins allows unexpected conclusions to be drawn about their functions. Viral envelope proteins protect the virus from attacks by cell defences. On the other hand, they package the virus into a transportable form. Certain domains of the envelope proteins also interact with receptor structures of the host cell. After a successful "docking manoeuvre", the viruses succeed in penetrating the target cell. Understanding these structural-functional relationships makes it possible to develop new remedies against viral infection - both in the form of new drugs and new vaccines.

Apart from the scientific recognition, the Paul Ehrlich and Ludwig Darmstaedter Prize has a very special meaning for Michael G. Rossmann, as he was born in Frankfurt, spent his first eight years of life here and his grandmother was friends with Paul Ehrlich's widow, Hedwig Ehrlich.