TY - JOUR
T1 - Structural basis of photosensitivity in a bacterial light-oxygen-voltage/ helix-turn-helix (LOV-HTH) DNA-binding protein
AU - Nash, Abigail I.
AU - McNulty, Reginald
AU - Shillito, Mary Elizabeth
AU - Swartz, Trevor E.
AU - Bogomolni, Roberto A.
AU - Luecke, Hartmut
AU - Gardner, Kevin H.
PY - 2011/6/7
Y1 - 2011/6/7
N2 - Light-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.
AB - Light-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.
KW - Allosteric regulation
KW - PER-ARNT-SIM domain
KW - Photosensing
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U2 - 10.1073/pnas.1100262108
DO - 10.1073/pnas.1100262108
M3 - Article
C2 - 21606338
AN - SCOPUS:79959354169
SN - 0027-8424
VL - 108
SP - 9449
EP - 9454
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 23
ER -