Dr. Roy Magnuson

Associate Professor, Biological Sciences Department


I am interested in addictive genetic elements and particularly in the plasmid addiction operon from the P1 plasmid of Escherichia. This operon encodes two small proteins: a stable, 126 amino acid toxin and an unstable 73 amino acid antidote. While the plasmid is present, the antidote is expressed in sufficient quantities to bind and neutralize the toxin. Upon plasmid loss, the continuing degradation of the antidote by the host-encoded ClpXP protease unveils the toxin, which then kills the plasmid-free segregant. Current research is focused on the structure and function of antidote and toxin, and on the regulatory circuits that govern the level of antidote and the ratio of antidote and toxin.

View Roy Magnuson's Curriculum Vitae


  • Ph.D., Biology, Massachusetts Institute of Technology, 1995
  • B.A., Integrated Science, Northwestern University, 1985
  • B.A., Biochemistry, Northwestern University, 1985

Classes Taught


  • Garcia-Pino, A., Y. Sterckx, R.D. Magnuson and R. Loris, 2013. “Type II Toxin- Antitoxin Loci: The phd/doc family”. In: Gerdes, K., Ed., 2013. Prokaryotic Toxin-Antitoxins, Springer-Verlag, Berlin & Heidelberg pp.157-176. Garcia-Pino, A., Balasubramanian, S., Wyns, L., Gazit, E., De Greve, H., Magnuson, R.D., Charlieer, D., van Nuland, N.A.J., Loris, R., 2010. "Allostery and Intrinsic Disorder Mediate Transcriptional Regulation by Conditional Cooperativity" Cell. 142(1):101-11.
  • Garcia-Pino, A., Dao-Thi, M. H., Gazit, E., Magnuson, R. D., Wyns, L., and Loris, R. 2008. Crystallization of Doc and the Phd-Doc toxin-antitoxin complex. Acta Crystallogr Sect F Struct Biol Cryst Commun 64, 1034-1038.
  • Garcia-Pino A, Christensen-Dalsgaard M, Wyns L, Yarmolinsky M, Magnuson RD, Gerdes K, Loris R. 2008. "Doc of Prophage P1 Is Inhibited by Its Antitoxin Partner Phd through Fold Complementation" Journal of Biological Chemistry 283(45):30821-7.
  • Chen Y., Kay Holtman C., Magnuson R.D., Youderian P.A. and Golden S.S. 2008. "The complete sequence and functional analysis of pANL, the large plasmid of the unicellular freshwater cyanobacterium Synechococcus elongatus PCC 7942" Plasmid 59(3):176-92.
  • Magnuson, R.D., 2007. "Hypothetical Functions of Toxin-Antitoxin Systems" J Bacteriol 189(17): 6089-6092.
  • Zhao, Xueyan and Magnuson, R. D. 2005. Percolation of the Phd Repressor- Operator Interface. Journal of Bacteriology, 187:1901-1912.
  • McKinley, James Estle and Magnuson, R. D. 2005. Characterization of the Phd Repressor-Antitoxin Boundary. Journal of Bacteriology 187:765-770.
  • Smith, J. A., and Magnuson, R. D. 2004. Modular Organization of the Phd Repressor/Antitoxin Protein. Journal of Bacteriology 186:2692-2698. Magnuson, R. and Yarmolinsky, M. B. 1998. Corepression the P1 Addiction Operon by Phd and Doc. Journal of Bacteriology 180:6342-6351.
  • Magnuson, R., Lehnherr, H., Mukhopadhyay, G. and Yarmolinsky, M. B. 1996. Autoregulation of the Plasmid Addiction Operon of Bacteriophage P1. Journal of Biological Chemistry 271:18705-18710.
  • Solomon, J., Magnuson, R., Srivastava, A. and Grossman, A. D. 1995. Convergent sensing pathways mediate response to two extracellular competence factors in Bacillus subtilis. Genes & Development 9: 547-558.
  • Magnuson, R., Solomon, J. and Grossman, A. D. 1994. Biochemical and genetic characterization of a competence pheromone from B. subtilis. Cell 77: 207-216. Grossman, A. D., Ireton, K., Hoff, E. F., LeDeaux, J. R., Rudner, D. Z., Magnuson, R. and Hicks, K. A. 1991. Signal transduction and the initiation of sporulation in Bacillus subtilis. Semin. Dev. Biol. 2: 31-36.
  • Nakano, M. M., Magnuson, R., Meyers, A., Curry, J., Grossman, A. D. and Zuber, P. 1991. srfA is an operon required for surfactin production, competence development, and efficient sporulation in Bacillus subtilis. J. Bacteriol. 173: 1770-1778.