The Fungal Phytochrome FphA fromAspergillus nidulans

Sonja Brandt, David von Stetten, Mina Günther, Peter Hildebrandt, Nicole Frankenberg-Dinkel
2008 Journal of Biological Chemistry  
The red light-sensing photoreceptor FphA from Aspergillus nidulans is involved in the regulation of developmental processes in response to light. Here we present extended biochemical and spectroscopic characterization of recombinant FphA using a synthetic gene with host-adapted codon usage. The recombinant photosensory domain FphAN753 was shown to display all features of a bona fide phytochrome. It covalently binds biliverdin as chromophore and undergoes red/far-red light-inducible
more » ... on with both parent states being protonated. The large N-terminal variable extension of FphA exerts a stabilizing effect on the active Pfr state. Upon substitution of the highly conserved histidine 504, involved in the hydrogen-bonding network of the protein moiety and the chromophore, chromophore attachment and photoreversibility were completely impaired. FphA is a functional sensor histidine kinase with a strong red-light-dependent autophosphorylation activity. Furthermore, intermolecular trans-phosphorylation to the response regulator domain of a second monomer could be demonstrated. Interestingly, co-incubation of FphA and FphA variants led to enhanced autophosphorylation, including the "inactive" Pr form. The latter observed phenomenon might suggest that auto-and trans-phosphorylation activity is modulated by additional interaction partners leading to variable phosphorylation events that trigger a specific output response.
doi:10.1074/jbc.m805506200 pmid:18931394 pmcid:PMC3259886 fatcat:5souzgipcjcyhi7mhp44nuvhii