LANTHANIDE-BASED RESONANCE ENERGY-TRANSFER

Fluorescence resonance energy transfer is a powerful tool for studying nanometer-scale distances in biological macromolecules under physiolo gical conditions, Using luminescent lanthanides instead of conventiona l fluorophores as donor molecules in energy transfer measurements offe rs many technical advantages and opens up a wide-range of new applicat ions, Lanthanide photophysics and the instrumentation underlying these advantages are discussed, One new application, the study of conformat ional changes in the large protein complex actomyosin, which is respon sible for muscle contraction and subcellular movement in many eucaryot es, is briefly discussed.