Enzyme-catalysed reaction for long-term fluorescent observation of single DNA molecules

The technical development of long-term fluorescent observation of single DNA molecules is central to fields ranging from molecular biological detection to understanding the physical properties of them under a microscope. Here, we address this challenge using protocatechuic acid and protocatechuate-3,4- dioxygenase (PADase) and demonstrate fluorescent lifetimes of dyed single DNA molecules of 150-180 s, three times longer than those without any treatments.