Characterization and antibacterial properties of LysinB protein in bacteriophage TM4
Objective To analyze the sequence of LysinB protein in bacteriophage TM4,express LysinB protein in E.coli and evaluate its bactericidal activity in vitro.Methods Bacteriophage TM4 LysinB gene was synthesized and the recombinant prokaryotic expression plasmid was constructed.The soluble protein was induced and purified.The biological characteristics of bacteriophage TM4 LysinB protein were analyzed by online software program.Mycobacterium smegmatis was cultured in 7H9 medium,and its bactericidal effect and stability were detected.Results The theoretical isoelectric point was 6.66,the instability index was 28.71,which was a stable and amphiphilic protein.In the secondary structure,The random coil,α-helix,β-fold and turn Angle accounted for 42.00%,40.25%,12.00%and 5.75%;In the tertiary structure,the content of random coil was high.The peptide composed of AA at positions 11 to 73 constituted the peptidoglycan binding domain.The regions of B cell epitopes and the strong binding peptides of T cell epitopes were predicted.LysinB protein has a significant ability to kill Mycobacterium smegmatis in vitro.PBST protein buffer with pH8.0 was beneficial to maintain the bactericidal effect of LysinB proteins during the experimental cycle.Conclusion This study expands the comprehensive understanding of the LysinB protein of mycobacterial phage TM4 lyase,and also provides reference for the development of stable storage of phage enzyme preparation and its clinical application.