Biochemical Characterization of RssA-RssB, a Two-Component Signal Transduction System Regulating Swarming Behavior in Serratia marcescens
| Autor: | Shen Wu Ho, Jun-Rong Wei, Yu Huan Tsai, Yu Tze Horng, Hsin-Chih Lai, Shang Chen Hsieh, Po-Chi Soo |
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| Rok vydání: | 2005 |
| Předmět: |
Base Sequence
biology Movement Molecular Sequence Data Mutant Swarming (honey bee) Promoter biology.organism_classification Microbiology DNA-binding protein DNA-Binding Proteins Response regulator Bacterial Proteins Biochemistry Mutagenesis Serratia marcescens Phosphorylation Amino Acid Sequence Signal transduction Promoter Regions Genetic Molecular Biology Signal Transduction Transcription Factors |
| Zdroj: | Journal of Bacteriology. 187:5683-5690 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.187.16.5683-5690.2005 |
| Popis: | Our previous study had identified a pair of potential two-component signal transduction proteins, RssA-RssB, involved in the regulation of Serratia marcescens swarming. When mutated, both rssA and rssB mutants showed precocious swarming phenotypes on LB swarming agar, whereby swarming not only occurred at 37°C but also initiated on a surface of higher agar concentration and more rapidly than did the parent strain at 30°C. In this study, we further show that the predicted sensor kinase RssA and the response regulator RssB bear characteristics of components of the phosphorelay signaling system. In vitro phosphorylation and site-directed mutagenesis assays showed that phosphorylated RssA transfers the phosphate group to RssB and that histidine 248 and aspartate 51 are essential amino acid residues involved in the phosphotransfer reactions in RssA and RssB, respectively. Accordingly, while wild-type rssA could, the mutated rssA (H248A) in trans could not complement the precocious swarming phenotype of the rssA mutant. Although RssA-RssB regulates expressions of shlA and ygfF of S. marcescens ( ygfF Sm ), in vitro DNA-binding assays showed that the phosphorylated RssB did not bind directly to the promoter regions of these two genes but bound to its own rssB promoter. Subsequent assays located the RssB binding site within a 63-bp rssB promoter DNA region and confirmed a direct negative autoregulation of the RssA-RssB signaling pathway. These results suggest that when activated, RssA-RssB acts as a negative regulator for controlling the initiation of S. marcescens swarming. |
| Databáze: | OpenAIRE |
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