3g6o

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Crystal structure of P. aeruginosa bacteriophytochrome PaBphP photosensory core domain mutant Q188L

Structural highlights

3g6o is a 2 chain structure with sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.85Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

BPHY_PSEAE Photoreceptor which exists in two forms that are reversibly interconvertible by light: the R form that absorbs maximally in the red region of the spectrum and the FR form that absorbs maximally in the far-red region (By similarity).

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Phytochromes are red-light photoreceptors that regulate light responses in plants, fungi, and bacteria by means of reversible photoconversion between red (Pr) and far-red (Pfr) light-absorbing states. Here, we report the crystal structure of the Q188L mutant of Pseudomonas aeruginosa bacteriophytochrome (PaBphP) photosensory core module, which exhibits altered photoconversion behavior and different crystal packing from wild type. We observe two distinct chromophore conformations in the Q188L crystal structure that we identify with the Pfr and Pr states. The Pr/Pfr compositions, varying from crystal to crystal, seem to correlate with light conditions under which the Q188L crystals are cryoprotected. We also compare all known Pr and Pfr structures. Using site-directed mutagenesis, we identify residues that are involved in stabilizing the 15Ea (Pfr) and 15Za (Pr) configurations of the biliverdin chromophore. Specifically, Ser-261 appears to be essential to form a stable Pr state in PaBphP, possibly by means of its interaction with the propionate group of ring C. We propose a "flip-and-rotate" model that summarizes the major conformational differences between the Pr and Pfr states of the chromophore and its binding pocket.

Conformational differences between the Pfr and Pr states in Pseudomonas aeruginosa bacteriophytochrome.,Yang X, Kuk J, Moffat K Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):15639-44. Epub 2009 Aug 31. PMID:19720999^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Yang X, Kuk J, Moffat K. Conformational differences between the Pfr and Pr states in Pseudomonas aeruginosa bacteriophytochrome. Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):15639-44. Epub 2009 Aug 31. PMID:19720999