Chemical biology and sensitive microscopy: How labeling and advanced microscopy techniques can synergistically drive the fi eld of biomolecular imaging. Major developments in the fi elds of protein engineering for fl uorescence labeling and advanced microscopy techniques, such as super-resolution microscopy, or single-molecule spectroscopy, have in the recent past allowed both areas to advance substantially. On pages 65–74, Milles and Lemke review the state of the art in both areas and evaluate how they can feedback on each other to fulfi ll the demands of precision single-molecule studies (lower left). While the modifi cation of proteins through unnatural amino acids offers the minimal possible modifi cation to which a fl uorophore can be attached (upper left), it also has the potential of labeling within living cells. The suitability of different fl uorescent dyes for super-resolution microscopy, as well as fl uorescence resonance energy transfer based approaches, is also reviewed with a view to multi-parameter single molecule microscopy inside the cell (right).

Cover by S. Milles and E. A. Lemke