Toolkit Items

AsLOV2 is the light-oxygen-voltage 2 photosensory domain from Avena sativa phototropin 1 used as a blue-light-responsive actuator in engineered fusion proteins. Blue-light activation drives allosteric conformational extension involving sequential unfolding of the N-terminal A'α helix and the C-terminal Jα helix, enabling conformational uncaging and related optogenetic control.

Molecular dynamics simulations were used as a computational design method to guide construction of the PiL[D24] photoswitchable mPKM2-LOV2 fusion reported in the 2017 FEBS Journal study. In that context, the simulations supported engineering of a light-responsive pyruvate kinase chimera that preserved LOV2 photoreactivity and showed illumination-dependent changes in enzyme activity.

LOV-SsrA is a photoswitchable peptide module in which the SsrA peptide is embedded within the AsLOV2 Jα helix to gate effector binding with light. The design preserves the AsLOV2 dark-state structure and exposes or activates peptide binding upon light-induced Jα helix unfolding.

Markov State Modeling (MSM) is a computational method applied with molecular dynamics simulations to resolve conformational dynamics in the AsLOV2 photosensory domain. In the cited 2023 study, MSM was used to explain blue-light-induced stepwise unfolding of the C-terminal Jα-helix and to identify seven structurally distinguishable unfolding states spanning initiation and post-initiation phases.

Time-resolved vibrational spectroscopy coupled with isotope labeling is an assay method used to resolve light-triggered structural dynamics in the Avena sativa LOV2 (AsLOV2) photosensory domain. In the cited study, it mapped structural evolution from 100 fs to 1 ms after optical excitation and supported a sequential allosteric model linking the flavin pocket to Jα-helix unfolding.

AsLOV2-Jα-Rac1 is an artificial fusion protein that connects the Avena sativa AsLOV2-Jα photosensor to the Rac1 GTPase to create a light-responsive signaling switch. Light-triggered structural changes in the LOV2 module disrupt steric inhibition of Rac1 and permit binding of the effector protein PAK1.

AQTrip is an engineered EL222 variant carrying V41I, L52I, A79Q, and V121I substitutions in the blue-light-responsive LOV–HTH transcription factor. It stabilizes the photoactivated state and, in the reported study, oligomerizes without DNA and forms an EL222 dimer–DNA complex in the presence of DNA substrates.

PA-Rac1 is an AsLOV2-Jα-regulated photoactivable Rac1 GTPase in which light-driven conformational changes in the LOV2 module relieve inhibition at the Rac1 switch II activation site. This release permits effector-protein binding and activates Rac1-associated signaling.

PiL[D24] is an engineered mammalian pyruvate kinase M2 (PKM2) photoswitch containing an internal insertion of the Avena sativa LOV2 light-sensing domain at position D24. Illumination preserves the LOV2 photoreaction and allosterically modulates PKM2 behavior, increasing pyruvate kinase activity and cellular labeling of pyruvate from glucose.