Internalization of a thiazole-modified peptide in Sinorhizobium meliloti occurs by BacA-dependent and -independent mechanisms

Silvia Wehmeier, Markus F F Arnold, Victoria L Marlow, Mustapha Aouida, Kamila Myka, Vivien Fletcher, Monica Benincasa, Marco Scocchi, Dindial Ramotar, Gail P Ferguson

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


BacA proteins play key roles in the chronic intracellular infections of Sinorhizobium meliloti, Brucella abortus and Mycobacterium tuberculosis within their respective hosts. S. meliloti, B. abortus and M. tuberculosis BacA-deficient mutants have increased resistance to the thiazole-modified peptide, bleomycin. BacA was previously hypothesised, but not experimentally verified, to be involved in bleomycin uptake. In this paper, we show that a BacA-dependent mechanism is the major route of bleomycin internalisation in S. meliloti. We also determined that the B. abortus and S. meliloti BacA proteins are functional homologs and that the B. abortus BacA protein is involved in the uptake of both bleomycin and proline-rich peptides. Our findings also provide evidence that there is a second, BacA-independent minor mechanism for bleomycin internalisation in S. meliloti. We determined that the BacA-dependent and -independent mechanisms of bleomycin uptake are energy-dependent, consistent with both mechanisms of bleomycin uptake involving transport systems.
Original languageEnglish
Pages (from-to)2702-2713
Number of pages12
Issue number9
Early online date27 May 2010
Publication statusPublished - Sept 2010


  • BY, BODIPY FL-N-(2-aminorthyl)maleimide
  • DAPI, 4',6'-diamidino-2-phenylindole
  • DNP, dinitrophenol
  • fluoro-BLM-A5, fluorescently labelled bleomycin A5
  • MMS, methyl methane sulfonate
  • NCR peptides, nodule-specific cysteine-rich peptides
  • TMD, transmembrane domain
  • VLCFA, very-long-chain fatty acid


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