Characterization of putative class II bacteriocins identified from a non-bacteriocin-producing strain Lactobacillus casei ATCC 334.
Several putative class II bacteriocin-like genes were identified in Lactobacillus casei ATCC 334, all of which might encode peptides with a double-glycine leader. Six peptides encoded by these genes were heterologously expressed in Escherichia coli and then partially purified in order to test their bacteriocin activity. The results revealed that the mature LSEI_2163 peptide was a class IId bacteriocin that exhibited antimicrobial activity against some lactobacilli and several Listeria species. Similarly, mature LSEI_2386 was a putative pheromone peptide that also had significant bacteriocin activity against several Listeria species. The activities of both peptides tolerated 121°C for 30 min but not treatment with proteinase K or trypsin. The two Cys residues located at positions 4 and 24 in the mature LSEI_2163 peptide were shown by mass spectrometry to form a disulfide bridge, which was required for optimal antibacterial activity. However, replacement of one or both Cys with Ser would cause significant reduction of the antibacterial activity, the reduction being greater when only one of the Cys residues (C4S) was replaced than when both (C4S/C24S) were replaced.
Institute of Molecular Medicine and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
Yang-Cheng
YC
Kuo
Cheng-Feng
CF
Liu
Jhao-Fen
JF
Lin
An-Chieh
AC
Li
Ta-Chun
TC
Lo
Thy-Hou
TH
Lin
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D003001:Cloning, Molecular; D004220:Disulfides / Q000032:analysis; D019286:Endopeptidase K / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006358:Hot Temperature; D007780:Lacticaseibacillus casei / Q000235:genetics* / Q000378:metabolism*; D008087:Listeria / Q000187:drug effects; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D055550:Protein Stability; D014357:Trypsin / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004220:Disulfides; D014357:Trypsin; D019286:Endopeptidase K