Role of small proteins in the stress response of Alphaproteobacteria
University of Gießen (Germany), Institute for Microbiology and Molecular Biology
This project will elucidate the role of small proteins in the stress response of Alphaproteobacteria. It will initially focus on the small DUF1127 (domain of unknown function) proteins, which are found in many Alpha- and Gammaproteobacteria and are structurally related to domains from eukaryotic RNA binding proteins.
The DUF1127 domain comprises 40 amino acids (aa), which either represent almost a complete protein of 45-50 aa or the C-terminal domain of proteins with 60-75 aa, in rare cases up to 100 aa. We will first concentrate on the elucidation of the function of the two DUF1127 proteins RSP_6037 and RSP_0557 in the facultative photosynthetic bacterium Rhodobacter sphaeroides, for which preliminary data are available. RSP_6037 is co-transcribed with 4 sRNAs (CcsR1-4) with a function in singlet oxygen and other stress responses. DUF1127 protein genes often co-localize with genes for CcsR homologs in genomes from Alphaproteobacteria (Billenkamp et al., 2015). In R. sphaeroides the sRNAs are generated by RNase E-mediated processing from the primary transcript and the RSP_6037 protein strongly affects their level. The second DUF1127 protein, RSP_0577, is also induced by several stresses (Müller et al., 2016), plays a role in stress defense and has a moderate effect on the levels of the CcsR sRNAs. While RSP_6037 is essential, RSP_0557 is not essential and not part of an operon. We want to test the hypothesis that the DUF1127 proteins are RNA binding proteins, which may affect RNA processing. However we will also consider an interaction of DUF1127 proteins to DNA or to other proteins.
- Billenkamp F, Peng T, Berghoff BA, Klug G (2015) A cluster of four homologous small RNAs modulates C1 metabolism and the pyruvate dehydrogenase complex in Rhodobacter sphaeroides under various stress conditions. J. Bacteriol. 197: 1839-1852
- Müller KM, Berghoff BA, Eisenhardt BD, Remes B, Klug G (2016) Characterization of Pos19- a small coding RNA in the oxidative stress response of R. sphaeroides. PLoS ONE 11:e0163425