Sensing environmental cues is critical for bacteria to survive under different environmental conditions. This MERIT extension application proposes continued analyses ofsignal transduction components that are used by bacteria to sense alterations of oxygen tension and light intensity. One crytical oxygen and light regulated metaboUc pathway that we study is the tetrapyrrole biosynthetic pathway that synthesizes important end products heme, vitamin 312 and chlorophyll. We are actively studying how oxygen and light responding signal transduction components control synthesis ofthese tetrapyrroles with a long-term goal ofunderstanding how cells coordinate their synthesis. Our laboratory studies several oxygen and light responding receptors that are present in a wide variety of bacteria including several important pathogens where they are Implicated in controlling virulence. This proposal uses a combination of genetics, biochemistry and structural biology methodologies to obtain detailed understandings of underlying molecular mechanisms used to sense changes in oxygen tension and light intensity. We also study how this information is transmitted to transcription factors that regulate tetrapyrrole gene expression in response to oxygen and light. During the past funding period, the Pi's laboratory successfully transitioned Into the field of structural biology resulting in published crystal structures ofseveral light responding transcription factors that we study. These structural approaches are providing the first detailed understanding of how blue Ught absorption drives alteration in gene expression in bacteria. We are taking similar approaches to obtain a detailed molecular understanding of how a change in oxygen tension is sensed and how this information is used to alter cellular physiology.

Public Health Relevance

This study provides molecular details of how bacteria sense changes in oxygen tension and light intensity that can affect the behaviour, survival and pathogenicity of a broad number of bacterial species.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Method to Extend Research in Time (MERIT) Award (R37)
Project #
Application #
Study Section
Special Emphasis Panel (NSS)
Program Officer
Reddy, Michael K
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Indiana University Bloomington
Schools of Arts and Sciences
United States
Zip Code
Cheng, Zhuo; Li, Keran; Hammad, Loubna A et al. (2014) Vitamin B12 regulates photosystem gene expression via the CrtJ antirepressor AerR in Rhodobacter capsulatus. Mol Microbiol 91:649-64
Zappa, S├ębastien; Bauer, Carl E (2013) The LysR-type transcription factor HbrL is a global regulator of iron homeostasis and porphyrin synthesis in Rhodobacter capsulatus. Mol Microbiol 90:1277-92
Yin, Liang; Dragnea, Vladimira; Feldman, George et al. (2013) Redox and light control the heme-sensing activity of AppA. MBio 4:e00563-13
Wu, Jiang; Cheng, Zhuo; Reddie, Khalilah et al. (2013) RegB kinase activity is repressed by oxidative formation of cysteine sulfenic acid. J Biol Chem 288:4755-62
Yin, Liang; Dragnea, Vladimira; Bauer, Carl E (2012) PpsR, a regulator of heme and bacteriochlorophyll biosynthesis, is a heme-sensing protein. J Biol Chem 287:13850-8
Yuan, Hua; Dragnea, Vladimira; Wu, Qiong et al. (2011) Mutational and structural studies of the PixD BLUF output signal that affects light-regulated interactions with PixE. Biochemistry 50:6365-75
Zappa, Sebastien; Li, Keran; Bauer, Carl E (2010) The tetrapyrrole biosynthetic pathway and its regulation in Rhodobacter capsulatus. Adv Exp Med Biol 675:229-50
Dragnea, Vladimira; Arunkumar, Alphonse I; Yuan, Hua et al. (2009) Spectroscopic studies of the AppA BLUF domain from Rhodobacter sphaeroides: addressing movement of tryptophan 104 in the signaling state. Biochemistry 48:9969-79
Masuda, Shinji; Berleman, James; Hasselbring, Ben M et al. (2008) Regulation of aerobic photosystem synthesis in the purple bacterium Rhodospirillum centenum by CrtJ and AerR. Photochem Photobiol Sci 7:1267-72
Swem, Lee R; Swem, Danielle L; Wu, Jiang et al. (2007) Purification and assays of Rhodobacter capsulatus RegB-RegA two-component signal transduction system. Methods Enzymol 422:171-83

Showing the most recent 10 out of 12 publications