John Helmann

John Helmann earned bachelor`s degrees in Chemistry and Biology (University of California, Santa Cruz) in 1982. He then joined the Department of Biochemistry at the University of California at Berkeley where he studied bacterial RNA polymerase with Dr. Michael Chamberlin and earned a Ph.D. in 1987. From 1987 to 1990, Dr. Helmann worked as a post-doctoral fellow with Dr. Christopher T. Walsh at the Harvard Medical School. His post-doctoral research, on the regulation of bacterial mercuric ion resistance determinants, was supported by the Jane Coffin Childs Memorial Medical Research Foundation. Dr. Helmann joined the Section of Microbiology at Cornell as an Assistant Professor in 1990 and joined the graduate field of Biochemistry, Molecular, and Cell Biology in 1991. He was promoted to Associate Professor in 1996 and Professor in 2002.

Research Focus

Our laboratory studies Bacillus subtilis, a Gram-positive soil bacterium and genetic model system. Major research efforts address the stress responses elicited by (i) antibiotics that affect the cell envelope, (ii) reactive oxygen species, or (iii) deficiency or excess of nutrient metal ions. For each stress response, we are interested in the global patterns of transcriptional control, the mechanisms of the corresponding regulatory proteins, and the roles of the induced pathways.

Teaching Focus

Graduate module in Bacterial Structure and Function (1 credit). Every Fall semester.

Selected Publications

Journal Publications

• Wendel, B. M., Pi, H., Krüger, L., Herzberg, C., Stülke, J., & Helmann, J. D. (2022). A Central Role for Magnesium Homeostasis during Adaptation to Osmotic Stress. mBio, 13(1), e0009222.
• Sachla, A. J., & Helmann, J. D. (2021). Resource sharing between central metabolism and cell envelope synthesis. Current opinion in microbiology, 60, 34–43.
• Gaballa, A., Su, T. T., & Helmann, J. D. (2021). The Bacillus subtilis monothiol bacilliredoxin BrxC (YtxJ) and the Bdr (YpdA) disulfide reductase reduce S-bacillithiolated proteins. Redox biology, 42, 101935.
• Willdigg, J. R., & Helmann, J. D. (2021). Mini Review: Bacterial Membrane Composition and Its Modulation in Response to Stress. Frontiers in molecular biosciences, 8, 634438.
• Sachla, A. J., Luo, Y., & Helmann, J. D. (2021). Manganese impairs the QoxABCD terminal oxidase leading to respiration-associated toxicity. Molecular microbiology, 116(3), 729–742.
• Sachla, A. J., Alfonso, A. J., & Helmann, J. D. (2021). A Simplified Method for CRISPR-Cas9 Engineering of Bacillus subtilis. Microbiology spectrum, 9(2), e0075421.
• Jung, W., Sengupta, K., Wendel, B. M., Helmann, J. D., & Chen, P. (2020). Biphasic unbinding of a metalloregulator from DNA for transcription (de)repression in Live Bacteria. Nucleic acids research, 48(5), 2199–2208.
• Makthal, N., Do, H., Wendel, B. M., Olsen, R. J., Helmann, J. D., Musser, J. M., & Kumaraswami, M. (2020). Group A Streptococcus AdcR Regulon Participates in Bacterial Defense against Host-Mediated Zinc Sequestration and Contributes to Virulence. Infection and immunity, 88(8), e00097-20.
• Patel, Y., Zhao, H., & Helmann, J. D. (2020). A regulatory pathway that selectively up-regulates elongasome function in the absence of class A PBPs. eLife, 9, e57902.
• Chandrangsu, P., Huang, X., Gaballa, A., & Helmann, J. D. (2019). Bacillus subtilis FolE is sustained by the ZagA zinc metallochaperone and the alarmone ZTP under conditions of zinc deficiency. Molecular Microbiology.
• Rojas-Tapias, D., & Helmann, J. D. (2019). Identification of novel Spx regulatory pathways in Bacillus subtilis uncovers a close relationship between the CtsR and Spx regulons. Journal of Bacteriology.
• Sachla, A., & Helmann, J. D. (2019). A bacterial checkpoint protein for ribosome assembly moonlights as an essential metabolite-proofreading enzyme. Nature Communications. 10:1526.
• Heng, Z., Roistacher, D., & Helmann, J. D. (2019). Deciphering the essentiality and function of the anti-σM factors in Bacillus subtilis. Molecular Microbiology.
• Pi, H., & Helmann, J. D. (2018). Genome-Wide Characterization of the Fur Regulatory Network Reveals a Link between Catechol Degradation and Bacillibactin Metabolism in Bacillus subtilis. mBio. 9:e01451-18.
• Patel, V., Wu, Q., Chandrangsu, P., & Helmann, J. D. (2018). A metabolic checkpoint protein GlmR is important for diverting carbon into peptidoglycan biosynthesis in Bacillus subtilis. PLOS Genetics. 14:e1007689.
• Zhao, H., Roistacher, D. M., & Helmann, J. D. (2018). Aspartate deficiency limits peptidoglycan synthesis and sensitizes cells to antibiotics targeting cell wall synthesis in Bacillus subtilis. Molecular Microbiology. 109:826-844.
• Rojas-Tapias, D. F., & Helmann, J. D. (2018). Stabilization of Bacillus subtilis Spx under cell wall stress requires the anti-adaptor protein YirB. PLOS Genetics. 14.
• Rojas-Tapias, D. F., & Helmann, J. D. (2018). Induction of the Spx regulon by cell wall stress reveals novel regulatory mechanisms in Bacillus subtilis. Molecular Microbiology. 107:659-674.
• Pi, H., & Helmann, J. D. (2017). Sequential induction of Fur-regulated genes in response to iron limitation in Bacillus subtilis. PNAS: Proceedings of the National Academy of Sciences of the United States of America. 114:12785-12790.