Functional expression and purification of tailor-made chimeric endolysin with the broad antibacterial spectrum

Developing chimeric lysins with a wide lytic spectrum is important in fighting against Gram-negative pathogenic bacteria. In the present work, a novel chimerical lysin, LytAmfi, was constructed by fusing the bacteriophage endolysin Lyt μ1/6 with an amphipathic cationic peptide derived from T4 lysozyme. The result showed that the LytAmfi had not only lytic activity similar to parental Streptomyces aureofaciens endolysin Lyt μ1/6 but also broadened lytic activity against Gram-negative strains. Our work demonstrated that generating a novel chimeric lysin with an extended lytic spectrum was workable by fusing an active modular endolysin with an amphipathic cationic peptide that could penetrate the outer membrane of Gram-negative bacteria including Escherichia coli, Pseudomonas agglomerans, Acinetobacter lwoffii, Hafnia alvei, Citrobacter freundii and enable access of the lysin to lyse the bacteria ‘from within’ the host cell without pre-treatment of its outer membrane. Therefore, lysins with an extended spectrum of lytic activity would be of appreciable therapeutic value.