Identification and nucleotide sequence of genes involved in the synthesis of lactocin 705, a two-peptide bacteriocin from Lactobacillus casei CRL 705

Abstract

The structural gene determinants of lactocin 705, a bacteriocin produced by Lactobacillus casei CRL 705, have been amplified from a plasmid of approximately 35 kb and sequenced. Lactocin 705 is a class IIb bacteriocin, whose activity depends upon the complementation of two peptides (705K and 705L) of 33 amino acid residues each. These peptides are synthesized as precursors with signal sequences of the double-glycine type, which exhibited high identities with the leader peptides of plantaricin S and J from Lactobacillus plantarum, brochocin C from Brochotrix campestris, sakacin P from Lactobacillus sake, and the competence stimulating peptides from Streptococcus gordonii and Streptococcus mitis. However, the two mature bacteriocins 705K and 705L do not show significant similarity to other sequences in the databases. ß

Purification and Genetic Characterization of Plantaricin NC8, a Novel Coculture-Inducible Two-Peptide Bacteriocin fromLactobacillus plantarumNC8

“…In contrast, the leader sequences of both the ␣ and ␤ peptides are very similar to the double-glycine type of those reported for other class IIb LAB bacteriocins (12,16,21,23,38,51).…”

“…Although no significant homology among the amino acid sequences of the mature peptides PLNC8␣ and PLNC8␤ and other known bacteriocins was found, the leader peptide was very similar to those from other class IIb bacteriocins (12,16,23,33,38,40,51). These N-terminal leader sequences show the consensus sequence (-LS-EL-I-GG), thus indicating that both peptides are processed and secreted out of the cell via a dedicated ABC transporter (29), which is a typical feature of most class I and class II bacteriocins.…”

A review of bacteriocinogenic lactic acid bacteria used as bioprotective cultures in fresh meat produced in Argentina

“…Lactocin 705 is a bacteriocin whose activity depends on the complementary action of two peptides (lac705a and lac705b) of 33 amino acid residues each. The structural genes of this non-lantibiotic bacteriocin associated with a plasmid of approximately 18.6 kb encode precursors of two proteins, lactocin 705a and lactocin 705b (Cuozzo, Sesma, Palacios, R. Holgado, & Raya, 2000). The bactericidal action of this two-component bacteriocin relies on the complementary action of two peptides which form poration complexes in the cytoplasmic membrane, thereby dissipating ion gradients and resulting in inhibition of the growth of target microorganisms.…”

Molecular View by Fourier Transform Infrared Spectroscopy of the Relationship between Lactocin 705 and Membranes: Speculations on Antimicrobial Mechanism

“…Many bacteriocins appear to elicit their lethal effects by permeabilizing the cell membrane of target organisms, in certain cases by targeting intermediates of cell wall biosynthesis (10,44) or possibly proteins of the sugar phosphotransferase systems (24,39). The meat isolate Lactobacillus curvatus CRL705 (formerly identified as Lactobacillus casei CRL705) produces lactocin 705, a small antimicrobial substance that belongs to the class IIb bacteriocins, whose activities depend upon the complementation of two peptides, termed Lac705␣ (GMSGYIQGIPDFLKGYLHGISAANKHK KGRLGY; pI ϭ 9.87) and Lac705␤ (GFWGGLGYIAGRVG AAYGHAQASANNHHSPING; pI ϭ 8.61) (17,18). Lactocin 705 exerted an inhibitory effect on the indicator strain Lactobacillus plantarum CRL691 with an optimal Lac705␣/Lac705␤ peptide ratio of 1 to 4.…”