Single-molecule FRETing for virology: 20 years of insight into protein structure and dynamics

Abstract

Although viral protein structure and replication mechanisms have been explored extensively with xray crystallography, cryo-EM and population imaging studies, these methods are often not able to distinguish dynamic conformational changes in real-time. Single-molecule fluorescence resonance energy transfer (smFRET) offers unique insights into interactions and states that may be missed in ensemble studies, such as nucleic acid or protein structure, and conformational transitions during folding, receptor-ligand interactions, and fusion. We discuss the application of smFRET to the study of viral protein conformational dynamics, with a particular focus on viral glycoprotein dynamics, viral helicases, proteins involved in HIV reverse transcription and the influenza RNA polymerase. smFRET experiments have played a crucial role in deciphering conformational changes in these processes, emphasising the importance of smFRET as a tool for helping to elucidate the life cycle of viral pathogens and helping to identify key anti-viral targets.