Ribonucleic acids (RNA) ensure that the blueprint in the cell nucleus is translated into vital proteins and that cell functions are regulated. However, little is known about the structure and function of particularly long RNAs, which consist of hundreds or thousands of building blocks. Chemists at the University of Bonn have now developed a new method for this purpose: They mark the complex molecules with tiny „flags“ and measure the distances between them with a „molecular ruler“. The results are published online in advance in the journal „Angewandte Chemie International Edition“. The print version will be published shortly.