Structural interpretation of fluorescence resonance-energy transfer measurements

Fluorescence resonance-energy transfer (FRET) has been widely used to determine distance information in macromolecular systems. However, little has been written about methods for combining FRET distances into coherent structural models. I argue that the methods used so far are inappropriate. This paper describes an algorithm specifically tailored for finding structures from FRET measurements. This algorithm finds structures which fit the experimentally measured parameter, the efficiency of energy transfer, rather than derived distances. The algorithm was implemented in Mathematica and applied to FRET distances obtained for the contractile protein actin. The approach used is applicable to other experimental techniques which measure distances between a relatively small number of loci.