Role of the semi-conserved histidine residue in the light-sensing domain of LitR, a MerR-type photosensory transcriptional regulator
Takano, Hideaki and Mise, Kou and Maruyama, Takafumi and Hagiwara, Kenta and Ueda, Kenji,, 162, 1500-1509 (2016),
doi = https://doi.org/10.1099/mic.0.000321,
publicationName = Microbiology Society,
issn = 1350-0872,
abstract= The LitR/CarH protein family transcriptional regulator is a new type of photoreceptor based on the function of adenosyl B12 (AdoB12) as a light-sensitive ligand. Here, we studied a semi-conserved histidine residue (His132) in the light-sensing (AdoB12-binding) domain at the C-terminus of LitR from a thermophilic Gram-negative bacterium, Thermus thermophilus HB27. The in vivo mutation of His132 within LitR caused a reduction in the rate of carotenoid production in response to illumination. BIAcore analysis revealed that the illuminated-LitRH132A possesses high DNA-binding activity compared to the wild-type protein. The subunit structure analysis showed that LitRH132A performed an incomplete subunit dissociation. The ability of LitRH132A to associate with AdoB12 was reduced compared with that of the wild-type protein in an equilibration dialysis experiment. Overall, these results suggest that His132 of LitR is involved in the association with AdoB12 as well as the light-sensitive DNA-binding activity based on oligomer dissociation.,
language=,
type=