Recombinant Bacitracin transport permease protein BcrC (bcrC)
Description
Structure and Homology
BcrC is a small hydrophobic protein (~23 kDa) with a conserved transmembrane domain structure. Key features include:
-
Sequence homology: BcrC shares ~30% identity with the Bacitracin Resistance Complex (Bcr) subunit from Bacillus licheniformis and ~80% identity with a putative permease in Salmonella typhimurium .
-
Membrane localization: Overexpressed recombinant BcrC in E. coli localizes to the cytoplasmic membrane, confirmed via radiolabeling and SDS-PAGE .
Mechanism of Action
BcrC modulates bacitracin resistance through two hypothesized pathways:
Expression Systems
-
Plasmid-based overexpression: In E. coli, recombinant BcrC expressed from multicopy plasmids (e.g., pT-bcrC) increased bacitracin resistance by 2–3 fold (MIC: 200 U/mL vs. wild-type 60–120 U/mL) .
-
His-tagged purification: His₆-BcrC expressed in E. coli demonstrated undecaprenyl pyrophosphate (UPP) phosphatase activity, critical for IPP recycling .
Key Findings
| Parameter | Value | Source |
|---|---|---|
| MIC (wild-type E. coli) | 60–120 U/mL | |
| MIC (BcrC overexpression) | 200 U/mL | |
| UPP phosphatase activity | 600-fold increase (recombinant) |
Genetic Disruption and Phenotypic Effects
-
Disruption of bcrC via kanamycin cassette insertion reduced bacitracin resistance by 50% (MIC: 60 U/mL) in E. coli .
-
Resistance restoration occurred only with functional bcrC complementation, confirming its specificity .
Regulatory Context
In Bacillus subtilis, bcrC expression is controlled by:
-
Sigma factors: σᴹ and σˣ regulate transcription, with σᴹ being primary under bacitracin stress .
-
Cross-species conservation: B. subtilis BcrC requires interaction with ATPase subunits (e.g., BceAB) for full resistance, unlike E. coli .
Applications and Implications
Product Specs
Note: While we prioritize shipping the format currently in stock, please specify your format preference in order notes for customized preparation.
Note: Standard shipping includes blue ice packs. Dry ice shipping requires prior arrangement and incurs additional charges.
If you require a specific tag, please inform us; we will prioritize its development.
