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Purification and Initial Characterization of a Putative Blue Light‐regulated Phosphodiesterase from Escherichia coli ¶
Author(s) -
Rajagopal Sudarshan,
Key Jason M.,
Purcell Erin B.,
Boerema David J.,
Moffat Keith
Publication year - 2004
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2004.tb00127.x
Subject(s) - escherichia coli , biochemistry , phosphodiesterase , flavin group , chemistry , context (archaeology) , blue light , flavin adenine dinucleotide , flavoprotein , biophysics , biology , enzyme , gene , cofactor , paleontology , physics , optics
The Escherichia coli protein YegF contains a photosensory flavin adenine dinucleotide (FAD)‐binding BLUF domain covalently linked to an EAL domain, which is predicted to have cyclic‐di‐guanosine monophosphate (GMP) phosphodiesterase activity. We have cloned, overexpressed and purified this protein, which we refer to as blue light‐regulated phosphodiesterase (Blrp) for its putative activity. Blrp undergoes a reversible photocycle after exposure to light in which the spectrum of its photostationary state and kinetics of recovery of the dark state are similar to those of the isolated BLUF domain of the AppA protein. Unlike the AppA BLUF domain, the chromophore environment in the context of full‐length Blrp is asymmetric, and the protein does not undergo any detectable global changes on exposure to blue light. When overexpressed in E. coli , Blrp copurifies with certain proteins which suggests that it plays a protective role in response to oxidative stress. Predicted proteins from Klebsiella pneumoniae and from a bacterium in the Sargasso Sea are similar to E. coli Blrp in both their BLUF and EAL domains, which suggests that blue light sensing in these bacteria may follow similar pathways.