3p7n
From Proteopedia
Crystal structure of light activated transcription factor El222 from Erythrobacter litoralis
Structural highlights
FunctionLVHTH_ERYLH Has reversible, light-dependent DNA-binding activity. Upon illumination an internal FMN-protein adduct is formed which changes the protein conformation so that the previously sequestered DNA-binding domain is free to bind DNA. Binds to sequences within in its own promoter when illuminated but not when it has been incubated in the dark.[1] Publication Abstract from PubMedLight-oxygen-voltage (LOV) domains are blue light-activated signaling modules integral to a wide range of photosensory proteins. Upon illumination, LOV domains form internal protein-flavin adducts that generate conformational changes which control effector function. Here we advance our understanding of LOV regulation with structural, biophysical, and biochemical studies of EL222, a light-regulated DNA-binding protein. The dark-state crystal structure reveals interactions between the EL222 LOV and helix-turn-helix domains that we show inhibit DNA binding. Solution biophysical data indicate that illumination breaks these interactions, freeing the LOV and helix-turn-helix domains of each other. This conformational change has a key functional effect, allowing EL222 to bind DNA in a light-dependent manner. Our data reveal a conserved signaling mechanism among diverse LOV-containing proteins, where light-induced conformational changes trigger activation via a conserved interaction surface. Structural basis of photosensitivity in a bacterial light-oxygen-voltage/helix-turn-helix (LOV-HTH) DNA-binding protein.,Nash AI, McNulty R, Shillito ME, Swartz TE, Bogomolni RA, Luecke H, Gardner KH Proc Natl Acad Sci U S A. 2011 Jun 7;108(23):9449-54. Epub 2011 May 23. PMID:21606338[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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