Toolkit Items

Light-harvesting complex II (LHCII) is the major chlorophyll a/b-binding photosynthetic antenna complex of plants that has been studied in isolated native and recombinant forms. The cited literature indicates that light induces reversible conformational changes in LHCII that expose its N-terminal phosphorylation site and can also promote formation of dimeric LHCII states with distinct chlorophyll excitation-quenching properties.

Molecular dynamics simulations combined with Markov state modeling were used to characterize blue-light-induced conformational switching in the Avena sativa LOV2 (AsLOV2) domain. This computation method resolved C-terminal Jα-helix unfolding into seven structurally distinguishable steps spanning initiation and post-initiation phases.

LOV2-based photoswitches are optogenetic switches engineered from the LOV2 photoreceptor domain to control biological activities with light. They repurpose endogenous light-induced conformational changes in LOV2 to generate new cellular outputs and have been developed on the basis of detailed biophysical characterization of the isolated domain.

YF1 is an engineered light-oxygen-voltage (LOV) histidine kinase that acts as a blue-light-regulated signaling switch. Available evidence indicates that blue-light input is transmitted through structural transitions in the photosensor and linker regions that control its signaling state.

Electron-electron double resonance (ELDOR) spectroscopy is a structural assay method that, when combined with site-directed spin labelling, was used to chart light-induced structural transitions in the engineered LOV histidine kinase YF1. In the cited study, it provided pairwise distance information used to model blue-light-driven quaternary rearrangements in a signaling photoreceptor.

Site-directed spin labelling, used with electron-electron double resonance (ELDOR) spectroscopy, is a structural assay method for charting blue-light-induced conformational changes in proteins. In the cited study, it was applied to the engineered LOV histidine kinase YF1 to obtain distance information on light-dependent structural transitions and quaternary rearrangements.

LOV2 is a blue-light-sensing Light-Oxygen-Voltage domain from phototropins, which are multidomain plant photoreceptors containing LOV1, LOV2, and a C-terminal serine/threonine kinase domain. In this native context, light activation of LOV2 induces structural changes that are transmitted to the kinase domain to regulate signaling.

Phytochromes are photoreceptor protein domains that absorb far-red and near-infrared light and have been used as molecular templates for engineered light-sensing probes. Their suitability for tool development is linked to a multidomain architecture and autocatalytic incorporation of linear tetrapyrrole chromophores.

LANS is a light-activated nuclear shuttle, or LOV/NLS switch, that uses blue light to control nuclear localization by uncaging a nuclear localization signal. It has been used to regulate transcription in yeast and to manipulate nuclear localization and cell fate in the C. elegans embryo, including light-dependent control of the native transcription factor LIN-1.

Photoswitchable peptides have been recognized for many years; however, their functional implementation in biological systems has only recently been achieved... These exciting proof-of-principle studies highlight the tremendous potential of photocontrollable peptides as optochemical tools for chemical biology and biomedicine.