Identification, characterisation and specificity of a cell wall lytic enzyme from Lactobacillus fermentum BR11.
Screening of a genomic library with an antiserum raised against whole Lactobacillus fermentum BR11 cells identified a clone expressing an immunoreactive 37-kDa protein. Analysis of the 3010-bp DNA insert contained within the clone revealed four open reading frames (ORFs). One ORF encodes LysA, a 303 amino acid protein which has up to 35% identity with putative endolysins from prophages Lj928 and Lj965 from Lactobacillus johnsonii and Lp1 and Lp2 from Lactobacillus plantarum as well as with the endolysin of Lactobacillus gasseri bacteriophage Phiadh. The immunoreactive protein was shown to be encoded by a truncated ORF downstream of lysA which has similarity to glutamyl-tRNA synthetases. The N-terminus of LysA has sequence similarity with N-acetylmuramidase catalytic domains while the C-terminus has sequence similarity with putative cell envelope binding bacterial SH3b domains. C-terminal bacterial SH3b domains were identified in the majority of Lactobacillus bacteriophage endolysins. LysA was expressed in Escherichia coli and unusually was found to have a broad bacteriolytic activity range with activity against a number of different Lactobacillus species and against Lactococcus lactis, streptococci and Staphylococcus aureus. It was found that LysA is 2 and 8000 times more active against L. fermentum than L. lactis and Streptococcus pyogenes, respectively.
Turner
Mark S
MS
Infectious Diseases Program, Faculty of Science, School of Life Sciences, Queensland University of Technology, G.P.O. Box 2434, Brisbane, Queensland 4001, Australia. ms.turner@qut.edu.au
Hafner
Louise M
LM
Walsh
Terry
T
Giffard
Philip M
PM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001435:Bacteriophages / Q000235:genetics; D001665:Binding Sites; D020134:Catalytic Domain; D002473:Cell Wall / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D023061:Gene Order; D005975:Glutamate-tRNA Ligase / Q000235:genetics; D007778:Lactobacillus / Q000201:enzymology* / Q000235:genetics*; D013294:Lactococcus lactis / Q000378:metabolism; D008969:Molecular Sequence Data; D009113:Muramidase / Q000235:genetics; D016366:Open Reading Frames; D039002:Prophages / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000378:metabolism; D013291:Streptococcus / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D014764:Viral Proteins; D009113:Muramidase; D010450:Endopeptidases; C001143:endolysin; D005975:Glutamate-tRNA Ligase