LOV Domains in the Design of Photoresponsive Enzymes

In nature, a multitude of mechanisms have emerged for regulating biological processes and, specifically, protein activity. Light as a natural regulatory element is of outstanding interest for studying and modulating protein activity because it can be precisely applied with regard to a site of action, instant of time, or intensity. Naturally occurring photoresponsive proteins, predominantly those containing a light-oxygen-voltage (LOV) domain, have been characterized structurally and mechanistically and also conjugated to various proteins of interest. Immediate advantages of these new photoresponsive proteins such as genetic encoding, no requirement of chemical modification, and reversibility are paid for by difficulties in predicting the envisaged activity or type and site of domain fusion. In this article, we summarize recent advances and give a survey on currently available design concepts for engineering photoswitchable proteins.