Functional cloning of Bacillus anthracis dihydrofolate reductase and confirmation of natural resistance to trimethoprim.

ABSTRACT: Bacillus anthracis is reported to be naturally resistant to trimethoprim (TMP), a drug that inhibits dihydrofolate reductase (DHFR), a key enzyme in the folate pathway. A microdilution broth assay established that the MIC of TMP for B. anthracis Sterne is >2,048 but < or =4,096 microg/ml. A putative DHFR sequence was amplified from B. anthracis Sterne genomic DNA. The PCR product was cloned into the Invitrogen pCRT7/CT-TOPO vector, followed by transformation into Escherichia coli TOP10F' chemically competent cells. Plasmid DNA from a clone showing the correct construct with a thrombin cleavage site attached downstream from the terminus of the cloned PCR product was transformed into E. coli BL21 Star (DE3)pLysS competent cells for expression of the six-histidine-tagged fusion protein and pu

SUBMITTER: Barrow EW 

PROVIDER: S-EPMC529193 | biostudies-literature | 2004 Dec

REPOSITORIES: biostudies-literature