%0 Journal Article %A Nissen-Meyer, Jon %A Larsen, Anette Granly %A Sletten, Knut %A Daeschel, Mark %A Nes, Ingolf F. %T Purification and characterization of plantaricin A, a Lactobacillus plantarum bacteriocin whose activity depends on the action of two peptides %D 1993 %J Microbiology, %V 139 %N 9 %P 1973-1978 %@ 1465-2080 %R https://doi.org/10.1099/00221287-139-9-1973 %I Microbiology Society, %X SUMMARY: A Lactobacillus plantarum bacteriocin, plantaricin A, has been purified to homogeneity by ammonium sulphate precipitation, binding to cation exchanger and Octyl-Sepharose, and reverse-phase chromatography. The bacteriocin activity was associated with two peptides, termed a and , which were separated upon reverse-phase chromatography. Bacteriocin activity required the complementary action of both the a and peptides. From the N-terminal end, 21 and 22 amino acid residues of a and , respectively, were sequenced. Further attempts at sequencing revealed no additional amino acid residues, suggesting that either the C terminus had been reached or that modifications in the next amino acid residue blocked the sequencing reaction. Judging from their amino acid sequence, a and may be encoded by the same gene, since a appeared to be a truncated form of . Alanine, the first amino acid residue at the N-terminal end of was not present at this position in a. Otherwise the sequences of a and appeared to be identical. The calculated molecular masses of the sequenced part of a and were 2426 and 2497 Da, respectively. The molecular masses of a and as determined by mass spectroscopy were 2687 30 and 2758 30 Da, respectively, indicating that (i) the only difference between a and was the presence of the N-terminal alanine residue in , and that (ii) in addition to the sequenced residues, two to three unidentified amino acid residues are present at the C-terminal ends of the a and peptides. Both a and may form amphiphilic a-helices, suggesting that they are pore-forming peptides that create cell membrane channels through a barrel-stave' mechanism. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-139-9-1973