Honors & Awards

  • 'Hermanas in STEM' Proposal awarded funding, Diversity Improvement Funds (VPGE), Stanford University (2015)
  • Bio-X Graduate Fellowship, Stanford Bio-X, Stanford University (2014-2015)
  • ADVANCE Fellow, Stanford University (2013)

Professional Affiliations and Activities

  • Co-President, Stanford Hermanas in STEM (2015 - Present)
  • Biology Liaison, Vice Provost for Teaching and Learning (2014 - 2016)
  • International Student Advocate, BioAIMs (2015 - 2016)
  • Career Development Chair, BioAIMs (2014 - 2015)

Stanford Advisors

All Publications

  • Role of Metal Ions on the Activity of Mycobacterium tuberculosis Pyrazinamidase AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE Sheen, P., Ferrer, P., Gilman, R. H., Christiansen, G., Moreno-Roman, P., Gutierrez, A. H., Sotelo, J., Evangelista, W., Fuentes, P., Rueda, D., Flores, M., Olivera, P., Solis, J., Pesaresi, A., Lamba, D., Zimic, M. 2012; 87 (1): 153-161


    Pyrazinamidase of Mycobacterium tuberculosis catalyzes the conversion of pyrazinamide to the active molecule pyrazinoic acid. Reduction of pyrazinamidase activity results in a level of pyrazinamide resistance. Previous studies have suggested that pyrazinamidase has a metal-binding site and that a divalent metal cofactor is required for activity. To determine the effect of divalent metals on the pyrazinamidase, the recombinant wild-type pyrazinamidase corresponding to the H37Rv pyrazinamide-susceptible reference strain was expressed in Escherichia coli with and without a carboxy terminal. His-tagged pyrazinamidase was inactivated by metal depletion and reactivated by titration with divalent metals. Although Co(2+), Mn(2+), and Zn(2+) restored pyrazinamidase activity, only Co(2+) enhanced the enzymatic activity to levels higher than the wild-type pyrazinamidase. Cu(2+), Fe(2+), Fe(3+), and Mg(2+) did not restore the activity under the conditions tested. Various recombinant mutated pyrazinamidases with appropriate folding but different enzymatic activities showed a differential pattern of recovered activity. X-ray fluorescence and atomic absorbance spectroscopy showed that recombinant wild-type pyrazinamidase expressed in E. coli most likely contained Zn. In conclusion, this study suggests that M. tuberculosis pyrazinamidase is a metalloenzyme that is able to coordinate several ions, but in vivo, it is more likely to coordinate Zn(2+). However, in vitro, the metal-depleted enzyme could be reactivated by several divalent metals with higher efficiency than Zn.

    View details for DOI 10.4269/ajtmh.2012.10-0565

    View details for Web of Science ID 000306153500026

    View details for PubMedID 22764307