2byc: Difference between revisions

Light is an essential environmental factor, and many species have evolved, the capability to respond to it. Blue light is perceived through three, flavin-containing photoreceptor families: cryptochromes, light-oxygen-voltage, and BLUF (sensor of blue light using flavin adenine, dinucleotide, FAD) domain proteins. BLUF domains are present in various, proteins from Bacteria and lower Eukarya. They are fully modular and can, relay signals to structurally and functionally diverse output units, most, of which are implicated in nucleotide metabolism. We present the high, resolution crystal structure of the dark resting state of BlrB, a short, BLUF domain-containing protein from Rhodobacter sphaeroides. The structure, reveals a previously uncharacterized FAD-binding fold. Along with other, lines of evidence, it suggests mechanistic aspects for the photocycle that, is characterized by a red-shifted absorbance of the flavin. The, isoalloxazine ring of FAD binds in a cleft between two helices, whereas, the adenine ring points into the solvent. We propose that the adenine ring, serves as a hook mediating the interaction with its effector/output, domain. The structure suggests a unique photochemical signaling switch in, which the absorption of light induces a structural change in the rim, surrounding the hook, thereby changing the protein interface between BLUF, and the output domain.

2BYC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodobacter_sphaeroides Rhodobacter sphaeroides] with FMN as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BYC OCA].  

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