Academic Appointments


  • Basic Life Science Research Associate, Biology

All Publications


  • Synergistic effects of soil microstructure and bacterial EPS on drying rate in emulated soil micromodels SOIL BIOLOGY & BIOCHEMISTRY Deng, J., Orner, E. P., Chau, J. F., Anderson, E. M., Kadilak, A. L., Rubinstein, R. L., Bouchillon, G. M., Goodwin, R. A., Gage, D. J., Shor, L. M. 2015; 83: 116-124
  • Biochemical Characterization of a Nitrogen-Type Phosphotransferase System Reveals that Enzyme EINtr Integrates Carbon and Nitrogen Signaling in Sinorhizobium meliloti JOURNAL OF BACTERIOLOGY Goodwin, R. A., Gage, D. J. 2014; 196 (10): 1901-1907

    Abstract

    In Sinorhizobium meliloti, catabolite repression is influenced by a noncanonical nitrogen-type phosphotransferase system (PTS(Ntr)). In this PTS(Ntr), the protein HPr is phosphorylated on histidine-22 by the enzyme EI(Ntr) and the flux of phosphate through this residue onto downstream proteins leads to an increase in succinate-mediated catabolite repression (SMCR). In order to explore the molecular determinants of HPr phosphorylation by EI(Ntr), both proteins were purified and the activity of EI(Ntr) was measured. Experimentally determined kinetic parameters of EI(Ntr) activity were significantly slower than those determined for the carbohydrate-type EI in Escherichia coli. Enzymatic assays showed that glutamine, a signal of nitrogen availability in many Gram-negative bacteria, strongly inhibits EI(Ntr). Binding experiments using the isolated GAF domain of EI(Ntr) (EIGAF) showed that it is the domain responsible for detection of glutamine. EI(Ntr) activity was not affected by α-ketoglutarate, and no binding between the EIGAF and α-ketoglutarate could be detected. These data suggest that in S. melilloti, EI(Ntr) phosphorylation of HPr is regulated by signals from both carbon metabolism (phosphoenolpyruvate) and nitrogen metabolism (glutamine).

    View details for DOI 10.1128/JB.01489-14

    View details for Web of Science ID 000334674700012

    View details for PubMedID 24633875