Fig. 3.

Gene cloning, protein expression and purification of MMPphg, the gene product of Meiothermus phage MMP17, and functional analysis of MMPphg as a metallopeptidase. a PCR amplification of MMPphg gene. b Lactose (1 g/L) was used for induction to overproduce MMPphg. c SDS-PAGE analysis of the purity of recombinant MMPphg, which is at approximately 26 kDa as the black arrowhead indicates. d MMPphg is able to digest cell wall (CW) extracted from Meiothermus sp. TG17, the host bacterium for phage MMP17. e Effects of metal ions on the lytic activity of MMPphg. Relative activity of MMPphg against Meiothermus sp. TG17 cells was calculated as percentage in relation to the non-treated control. Each experiment was repeated in triplicate; error bars indicate the standard deviation. P values were determined using the Student’s t test. ***, P < 0.001; ND, non-detectable; NS, not significant