Three putative photosensory light, oxygen or voltage (LOV) domains with distinct biochemical properties from the filamentous cyanobacterium Anabaena sp. PCC 7120.
Light, oxygen or voltage (LOV) domains function as blue-light sensors in the phototropin family of photoreceptors found in plants, algae and bacteria. We detected putative LOV domains (Alr3170-LOV, All2875-LOV and Alr1229-LOV) in the genome of a filamentous cyanobacterium, Anabaena sp. PCC 7120. These cyanobacterial LOV domains are closely clustered with the known LOV domains. Alr3170-LOV and A112875-LOV carry the conserved cysteine residue unique to the photoactive LOV, whereas Alr1229-LOV does not. We expressed these three LOV domains in Escherichia coli and purified them. In fact, Alr3170-LOV and A112875-LOV that are conserved in Nostoc punctiforme, a related species, bound flavin mononucleotide and showed spectral changes unique to known LOV domains on illumination with blue light. Alr3170-LOV was completely photoreduced and dark reversion was slow, whereas A112875-LOV was slowly photoreduced and dark reversion was rapid. For comparison, AvA112875-LOV in a closely related A. variabilis was also studied as a homolog of A112875-LOV. Finally, we observed that Alr1229-LOV that is not conserved in N. punctiforme showed no flavin binding.
Narikawa
Rei
R
Department of Life Sciences (Biology), Graduate School of Art and Sciences, University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan.
Zikihara
Kazunori
K
Okajima
Koji
K
Ochiai
Yuriko
Y
Katayama
Mitsunori
M
Shichida
Yoshinori
Y
Tokutomi
Satoru
S
Ikeuchi
Masahiko
M
D000595:Amino Acid Sequence; D017033:Anabaena / Q000145:classification / Q000378:metabolism* / Q000528:radiation effects; D017124:Conserved Sequence; D056931:Cryptochromes; D005420:Flavoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D015964:Gene Expression Regulation, Bacterial; D008027:Light; D008969:Molecular Sequence Data; D010100:Oxygen / Q000494:pharmacology; D010802:Phylogeny; D010957:Plasmids; D016415:Sequence Alignment
D056931:Cryptochromes; D005420:Flavoproteins; D010100:Oxygen