Ribosomally synthesized and post-translationally modified peptide natural products: Overview and recommendations for a universal nomenclature

Covering: 1988 to 2012 This review presents recommended nomenclature for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), a rapidly growing class of natural products. The current knowledge regarding the biosynthesis of the >20 distinct compound classes is also reviewed, and commonalities are discussed

Transcriptional and regulatory studies of the genetic elements involved in the lysogenic-lytic commitment and the identification of the cro-like protein ORF76 of the temperate lactococcal bacteriophage ΦLC3

A transcriptional analysis of the lysogeny-related genes of the temperate bacteriophage Lactococcus lactis phiLC3 was performed using Northern blot hybridization during lysogeny and lytic infection by the phage. The lysogeny-related gene cluster was found to contain four promoters (P(1), P(2), Pint and P(173)), while the P(87) promoter directed transcription of orf80 and the putative gene orf87, which are located between the integrase gene and the cell lysis genes. The start sites of the transcripts were determined by primer extension. The divergently oriented lysogenic P(1) and lytic P(2) promoters located in the genetic switch region are responsible for transcription of orf286 which encodes the phage repressor, and the genes orf63 - orf76 - orf236 - orf110 - orf82 - orf57, respectively, while orf173 is transcribed from P(173). orf76 was identified as the gene encoding the Cro-like protein of phiLC3, and it was shown that ORF76 is able to bind specifically to the genetic switch region, albeit with lower affinity than does the phage repressor ORF286. ORF76 also competed with ORF286 for binding to this region. The functionality of P(1) and P(2), and their regulation by ORF286 and ORF76, was investigated using a reporter gene. In general, P(2) was a stronger promoter than P(1), but expression from both promoters, especially P(2), was regulated and modulated by flanking sequences and the presence of orf286 and orf76. ORF286 and ORF76 were both able to repress transcription from P(1) and P(2), while ORF286 was able to stimulate its own synthesis by tenfold. This work reveals the complex interplay between the regulatory elements that control the genetic switch between lysis and lysogeny in phiLC3 and other temperate phages of Lactococcus

Pediocin PA-1, a bacteriocin from Pediococcus acidilactici PAC1.0, forms hydrophilic pores in the cytoplasmic membrane of target cells.

Pediocin PA-1 is a bacteriocin which is produced by Pediococcus acidilactici PAC1.0. We demonstrate that pediocin PA-1 kills sensitive Pediococcus cells and acts on the cytoplasmic membrane. In contrast to its lack of impact on immune cells, pediocin PA-1 dissipates the transmembrane electrical potential and inhibits amino acid transport in sensitive cells. Pediocin interferes with the uptake of amino acids by cytoplasmic membrane vesicles derived from sensitive cells, while it is less effective with membranes derived from immune cells. In liposomes fused with membrane vesicles derived from both sensitive and immune cells, pediocin PA-1 elicits an efflux of small ions and, at higher concentrations, an efflux of molecules having molecular weights of up to 9,400. Our data suggest that pediocin PA-1 functions in a voltage-independent manner but requires a specific protein in the target membrane