The bacterial counterparts of plant phototropins.
We review and analyze the growing family of bacterial proteins carrying the LOV (light oxygen voltage) motif, a flavin-binding photoactive domain first characterized in plant blue-light receptors, the phototropins. A total of 29 sequences encoding LOV-proteins can be detected in the genomes of 24 bacterial species. In the bacterial LOV domains, the majority of the amino acids known to interact with the flavin mononucleotide (FMN) chromophore in phototropin LOVs are conserved, supporting the suggestion of their possible role as blue-light sensors. The Bacillus subtilis protein YtvA has been the first bacterial LOV-protein shown to bind FMN and to undergo the same light-induced reactions as plant phototropins. The photocycle involves the reversible formation of a covalent adduct between FMN and a conserved cysteine. In this work we report preliminary results on a Caulobacter crescentus LOV-kinase, that undergoes the same photochemistry as YtvA. The bacterial LOV-proteins exhibit a variety of effector domains associated to the light-responsive LOV-domain, e.g. histidine kinase, transcriptional regulators, putative phosphodiesterases and regulators of stress factors, pointing to their physiological role as sensing and signalling proteins.
Losi
Aba
A
Department of Physics, University of Parma, Istituto Nazionale per la Fisica della Materia, Parco Area delle Scienze 7/A, 43100, Parma, Italy. losia@fis.unipr.it
D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics; D018407:Bacterial Physiological Phenomena; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D001683:Biological Clocks; D017124:Conserved Sequence; D056931:Cryptochromes; D005420:Flavoproteins / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D008969:Molecular Sequence Data; D010101:Oxygen Consumption; D010777:Photochemistry; D018521:Plant Physiological Phenomena; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D056931:Cryptochromes; D005420:Flavoproteins