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Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein
10:43

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein

Published on: December 3, 2010

Mitomycin resistance in Streptomyces lavendulae includes a novel drug-binding-protein-dependent export system

P J Sheldon1, Y Mao, M He

  • 1Department of Microbiology and Biological Process Technology Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA.

Journal of Bacteriology
|April 10, 1999
PubMed

Insights

Researchers discovered a new mitomycin C (MC) transport gene (mct) in Streptomyces lavendulae. This gene, along with mrd, forms a novel export system, enhancing resistance to the antibiotic MC.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Streptomyces lavendulae produces the antibiotic mitomycin C (MC).
  • A previously identified mitomycin resistance locus, mrd, encodes a mitomycin-binding protein.
  • Understanding MC resistance mechanisms is crucial for antibiotic development and application.

Purpose of the Study:

  • To identify and characterize novel genes involved in mitomycin C resistance in Streptomyces lavendulae.
  • To elucidate the function of the putative mitomycin C transport gene (mct) and its role in conjunction with mrd.

Main Methods:

  • Sequence analysis of Streptomyces lavendulae NRRL 2564 chromosomal DNA.
  • Insertional inactivation of the putative mct gene in S. lavendulae.
  • Expression of mct and coexpression of mct and mrd in Escherichia coli.
  • Assays for cellular resistance to MC and intracellular drug accumulation.

Main Results:

  • A novel gene, mct, encoding a putative MC transporter with similarity to actinomycete antibiotic exporters was identified.
  • Disruption of mct increased sensitivity to MC in S. lavendulae.
  • Expression of mct in E. coli conferred MC resistance and reduced intracellular drug accumulation.
  • Coexpression of mct and mrd in E. coli resulted in a significant increase in MC resistance (150-fold).

Conclusions:

  • The mct gene encodes a novel MC transporter.
  • MRD and Mct function together as a specific export system for mitomycins.
  • This discovery provides insights into bacterial resistance mechanisms against antibiotics.

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