The AppA and PpsR Proteins from Rhodobacter sphaeroides Can Establish a Redox-Dependent Signal Chain but Fail To Transmit Blue-Light Signals in Other Bacteria
- 15 March 2007
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 189 (6), 2274-2282
- https://doi.org/10.1128/jb.01699-06
Abstract
The AppA protein of Rhodobacter sphaeroides has the unique ability to sense and transmit redox and light signals. In response to decreasing oxygen tension, AppA antagonizes the transcriptional regulator PpsR, which represses the expression of photosynthesis genes, including the puc operon. This mechanism, which is based on direct protein-protein interaction, is prevented by blue-light absorption of the BLUF domain located in the N-terminal part of AppA. In order to test whether AppA and PpsR are sufficient to transmit redox and light signals, we expressed these proteins in three different bacterial species and monitored oxygen- and blue-light-dependent puc expression either directly or by using a luciferase-based reporter construct. The AppA/PpsR system could mediate redox-dependent gene expression in the alphaproteobacteria Rhodobacter capsulatus and Paracoccus denitrificans but not in the gammaproteobacterium Escherichia coli . Analysis of a prrA mutant strain of R. sphaeroides strongly suggests that light-dependent gene expression requires a balanced interplay of the AppA/PpsR system with the PrrA response regulator. Therefore, the AppA/PpsR system was unable to establish light signaling in other bacteria. Based on our data, we present a model for the interdependence of AppA/PpsR signaling and the PrrA transcriptional activator.Keywords
This publication has 47 references indexed in Scilit:
- Redox properties of the Rhodobacter sphaeroides transcriptional regulatory proteins PpsR and AppAPhotosynthesis Research, 2006
- Tetrapyrrole Biosynthesis in Rhodobacter capsulatus Is Transcriptionally Regulated by the Heme-Binding Regulatory Protein, HbrLJournal of Bacteriology, 2006
- Tryptophan at Position 104 is Involved in Transforming Light Signal into Changes of β-sheet Structure for the Signaling State in the BLUF Domain of AppAPlant and Cell Physiology, 2005
- Adenosine diphosphate moiety does not participate in structural changes for the signaling state in the sensor of blue-light using FAD domain of AppAFEBS Letters, 2005
- Structure of a Novel Photoreceptor, the BLUF Domain of AppA fromRhodobacter sphaeroides,Biochemistry, 2005
- Photocycle of the Flavin-Binding Photoreceptor AppA, a Bacterial Transcriptional Antirepressor of Photosynthesis GenesBiochemistry, 2005
- RegB/RegA, a Highly Conserved Redox-Responding Global Two-Component Regulatory SystemMicrobiology and Molecular Biology Reviews, 2004
- Spectroscopic and Mutational Analysis of the Blue-Light Photoreceptor AppA: A Novel Photocycle Involving Flavin Stacking with an Aromatic Amino AcidBiochemistry, 2003
- Regulation of bacterial photosynthesis genes by oxygen and lightFEMS Microbiology Letters, 1999
- Directed Mutational Analysis of Bacteriochlorophyll a Biosynthesis in Rhodobacter capsulatusJournal of Molecular Biology, 1994