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From 2011.igem.org

Lov 2 Domain

Fluorescent proteins have transformed our ability to visualise, quantify and monitor expression of proteins and other molecules within cells. One of the more commonly used fluorescent proteins is GFP (Green Fluorescent Protein)

Plants contain a vast array of different photoreceptors which allow them to detect light around them in order to induce responses. One class of such receptors is the phototropins (phot1 and phot2). These are blue-light responsive domains which allow responses such as phototropism (the unidirectional movement of plants in response to blue light).

Phototropins are structurally made up of two regions: a photosensory domain (N-Terminus) and a serine/threonine kinase domain (C-Terminus).

The photosensory region consists of two LOV domains (Light, oxygen and voltage domain) known as LOV1 and LOV2 which are each ~110 amino acids long. These domains are a subgroup of the larger receptor group known as the PAS family, because they are associated with co-factor binding. Each of the two LOV domains acts by binding a flavin mononucleotide (FMN) in order to form a covalent adduct with a conserved cysteine residue.

Research was carried out to investigate the roles played by both LOV domains in phototropism, and it was found that LOV 2 of both phot1 and phot2 plays a significant role, whereas LOV on only plays a role in phot1 (Cho et al 2007)

LOV domain activity can be monitored by fluorescence. In darkenss, FMN binds non-covalently, and upon irradiation with light, this binds covalently. This bound FMN co-factor is what gives the green fluorescence

References

Cho, H.-Y., Tseng, T.S., Kaiserli, E., Sullivan, J., Christie, J.M. and Briggs, W.R. (2007) Physiological roles of the light, oxygen, or voltage domains of phototropin 1 and phototropin 2 in Arabidopsis1. Plant Physiology, 143 (1). pp. 517-529. ISSN 0032-0889

File:Lov2.jpg </br></br> Figure 1: (A) Diagram showing the structure of the blue light receptive phototropin. (B) Diagram showing the structure of the LOV2 domain with bound FMN co-factor. (Image by Dr John Christie, University of Glasgow)</br></br>

</br></br> Figure 2: Diagram showing phototropism (unidirectional bending) of an oat seedling in response to blue light. (Image by Dr John Christie, University of Glasgow) </br></br>

File:ILOVandLOV2.jpg