Internalization of a thiazole-modified peptide in Sinorhizobium meliloti occurs by BacA-dependent and -independent
Silvia Wehmeier1, Markus F F Arnold1, Victoria L Marlow1
1School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
Abstract:
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 has been previously hypothesized, 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 internalization in S. meliloti. We also determined that the B. abortus and S. meliloti BacA proteins are functional homologues 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 internalization 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.
Related Concept Videos
Protein Transport to the Inner Chloroplast Membrane
ABC Transporters: Importer
In bacteria, based on the number of transmembrane helices and the chemical nature of their substrates, the ABC importers can be divided into three types:
Microbe-Plant Interactions
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Regulation of Bacterial Virulence
Protein Transport to the Thylakoids


