Functional analysis of a putative holin-like peptide-coding gene in the genome of Bacillus licheniformis AnBa9
BhlA, a putative holin-like protein of Bacillus licheniformis AnBa9 expressed in Escherichia coli BL21(DE3) showed antibacterial activity against several gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and Micrococcus luteus. Deletion analysis of bhlA suggests that a hydrophobic transmembrane domain, BhlATM is essential for antibacterial activity. Though the minimum inhibitory concentration (MIC) of BhlA was sevenfold lower than BhlATM, transmembrane domain deleted construct (BhlA∆TM) had no antibacterial activity. The expression of BhlA in E. coli was found to be toxic to cells. Therefore, the bhlA was cloned in yeast surface display vector pYD1 and expressed in Saccharomyces cerevisiae. The surface displayed yeast showed inhibition of several gram-positive bacteria. This recombinant yeast expressing BhlA may be used as biodrug for efficient control of multiple drug-resistant bacterial infections.
KeywordsBacillus licheniformis BhlA Holin-like protein Transmembrane domain Antibacterial activity Yeast surface display
This work was supported by a grant from the Department of Science and Technology, India under OYS (SR/FT/L-98/2004) to TA. Support facility from Centre for Excellence in Genomic Sciences, Networking Resource Centre in Biological Sciences, Madurai Kamaraj University is gratefully acknowledged.
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