High specificity of bacteriophages for infection of their bacterial host species incurs diagnostic and therapeutic values. Usage of bacteriophages to combat bacterial infections has a long history whereas a novel promising area of research is the utilization of the whole bacteriophages or their parts as immunoaffinity reagents to diagnose bacterial infections, e.g. anthrax. Gamma-bacteriophage of Bacillus anthracis has an amazing capacity to attack this pathogen which is either in a vegetative state or in the form of spores, and γ-bacteriophage effectively reduces bacterial load. One of the crucial components of γ-bacteriophage, which determines its specificity, is a peptide LKMTADFILQ which resides at the C-terminus of the phage-encoded murein hydrolase (lysin). A recombinant C-terminal fragment of the γ-bacteriophage-encoded N-acetylmuramic-L-alanine amidase (lysin) was produced. A DNA fragment containing lysin gene (PlyG) was synthesized de novo. PlyG gene was cloned into expression plasmids pET32 and pET28 and the resulting constructs were transformed into Escherichia coli strain BL21(DE3). Recombinant expression products were purified using immobilized metal affinity chromatography (IMAC) and confirmed by denaturing gel electrophoresis and peptide mass-spectrometry. As a result, strains producing the C-terminal fragment of γ-bacteriophage PlyG lysin were obtained. Molecular masses of the expression products were 30 kDa for the pET32-based construct and 16 kDa for the pET28-based construct. Comparison of tryptic peptides’ mass-spectra with data from the Swiss Prot database using Mascot software confirmed that the obtained recombinant proteins contain amino acid sequences of the lysin.
View Full Article