BhlA holin family

The BhlA Holin Family (TC# 1.E.27) is named after putative holin-like peptides encoded in bacteria with bacteriocin similarities. BhlA proteins are generally about 67 to 80 amino acyl residues (aas) in length and exhibit a single N-terminal transmembrane segment (TMS). BhlA (TC# 1.E.27.1.4), a putative holin-like protein of Bacillus licheniformis expressed in Escherichia coli BL21(DE3) showed antibacterial activity against several Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and Micrococcus luteus. To analyze the effect of BhlA on bacteria cell, its ORF was cloned and expressed in Escherichia coli BL21(DE3). Expression of holin-like peptide, BhlA, was found to be toxic to the host cell. The site of action of BhlA is on the cell membrane and caused bacterial death by cell membrane disruption as clearly demonstrated by transmission electron microscopy. A representative list of proteins belonging to this family can be found in the Transporter Classification Database.