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Identification and characterization of a novel toxin–antitoxin module from Bacillus anthracis
Author(s) -
Agarwal Shivangi,
Agarwal Shivani,
Bhatnagar Rakesh
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.03.051
Subject(s) - bacillus anthracis , biology , antitoxin , dna , anthrax toxin , escherichia coli , gene , genetics , microbiology and biotechnology , toxin , fusion protein , recombinant dna , bacteria
Comparative genome analysis of Bacillus anthracis revealed a pair of linked genes encoding pemK (K, killer protein) and pemI (I, inhibitory protein) homologous to pem loci of other organisms. Expression of PemK in Escherichia coli and Bacillus anthracis was bacteriostatic whereas the concomitant expression of PemI reversed the growth arrest. PemK expression effectively inhibited protein synthesis with no significant effect on DNA replication. Coexpression and interaction of these proteins confirmed it to be a Type II addiction module. Thermal denaturation analysis reflected poor conformational stability of PemI as compared to PemK. Circular dichroism analysis indicated that PemI contains twice the amount of β‐sheets as PemK. Gel retardation assays demonstrated that PemI binds to its upstream DNA sequence. This study reports the first evidence of an active chromosome encoded toxin–antitoxin locus in B. anthracis .