Ligand binding to either of the two yeast pheromone GPCRs triggers the exchange of GTP for GDP on the Gα subunit and dissociation of Gα∙GTP from the Gβγ complex.

TLS Online TPP Program

#Id: 9857

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phot1 is the primary phototropic receptor mediates phototropism in response to low and high fluence rates of blue light. 

phot2 mediates phototropism in response to high light intensities

TLS Online TPP Program

#Id: 9858

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Phototropin receptors are associated with the plasma membrane, where they function as light-activated serine/threonine kinases.

TLS Online TPP Program

#Id: 9859

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Phototropin contains two light-sensing LIGHT-OXYGEN-VOLTAGE (LOV) domains, LOV1 and LOV2, each binding a chromophore flavin mononucleotide (FMN).

TLS Online TPP Program

#Id: 9860

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In the dark, the maximum absorption of the FMN chromophore is around 450 nm. 

Blue light induces the formation of a covalent bond between FMN and a cysteine residue, shifting the absorption maximum to 390 nm via a LOV660 intermediate form. The reaction is reversible in darkness.

TLS Online TPP Program

#Id: 9861

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LOV2 domain is essential for blue light–induced kinase activation and autophosphorylation of the phototropin photoreceptor.

TLS Online TPP Program

#Id: 9862

#XL - R Botany