Characterization of the Novel Leaderless Bacteriocin, Bawcin, from .

The rise of drug-resistant bacteria is a major threat to public health, highlighting the urgent need for new antimicrobial compounds and treatments. Bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by bacteria, hold promise as alternatives to conventional antibiotics. In this study, we identified and characterized a novel leaderless bacteriocin, bawcin, the first bacteriocin to be characterized from a species.

Unexpected Methyllanthionine Stereochemistry in the Morphogenetic Lanthipeptide SapT.

Lanthipeptides are polycyclic peptides characterized by the presence of lanthionine (Lan) and/or methyllanthionine (MeLan). They are members of the ribosomally synthesized and post-translationally modified peptides (RiPPs). The stereochemical configuration of (Me)Lan cross-links is important for the bioactivity of lanthipeptides.

Transporter Protein-Guided Genome Mining for Head-to-Tail Cyclized Bacteriocins.

Head-to-tail cyclized bacteriocins are ribosomally synthesized antimicrobial peptides that are defined by peptide backbone cyclization involving the N- and C- terminal amino acids. Their cyclic nature and overall three-dimensional fold confer superior stability against extreme pH and temperature conditions, and protease degradation. Most of the characterized head-to-tail cyclized bacteriocins were discovered through a traditional approach that involved the screening of bacterial isolates for antimicrobial activity and subsequent isolation and characterization of the active molecule.

Correction: Structural determinants of macrocyclization in substrate-controlled lanthipeptide biosynthetic pathways.

[This corrects the article DOI: 10.1039/D0SC01651A.].

Structural determinants of macrocyclization in substrate-controlled lanthipeptide biosynthetic pathways.

Lanthipeptides are characterized by thioether crosslinks formed by post-translational modifications. The cyclization process that favors a single ring pattern over many other possible ring patterns has been the topic of much speculation. Recent studies suggest that for some systems the cyclization pattern and stereochemistry is determined not by the enzyme, but by the sequence of the precursor peptide.

Substrate Recognition by the Class II Lanthipeptide Synthetase HalM2.

Class II lanthipeptides belong to a diverse group of natural products known as ribosomally synthesized and post-translationally modified peptides (RiPPs). Most RiPP precursor peptides contain an N-terminal recognition sequence known as the leader peptide, which is typically recognized by biosynthetic enzymes that catalyze modifications on the C-terminal core peptide. For class II lanthipeptides, these are carried out by a bifunctional lanthipeptide synthetase (LanM) that catalyzes dehydration and cyclization reactions on peptidic substrates to generate thioether-containing, macrocyclic molecules.

-Methyltransferase-Mediated Incorporation of a β-Amino Acid in Lanthipeptides.

Lanthipeptides represent a large class of cyclic natural products defined by the presence of lanthionine (Lan) and methyllanthionine (MeLan) cross-links. With the advances in DNA sequencing technologies and genome mining tools, new biosynthetic enzymes capable of installing unusual structural features are continuously being discovered. In this study, we investigated an -methyltransferase that is a member of the most prominent auxiliary enzyme family associated with class I lanthipeptide biosynthetic gene clusters.

Characterization of a Dehydratase and Methyltransferase in the Biosynthesis of Ribosomally Synthesized and Post-translationally Modified Peptides in Lachnospiraceae.

As a result of the exponential increase in genomic data, discovery of novel ribosomally synthesized and post-translationally modified peptide natural products (RiPPs) has progressed rapidly in the past decade. The lanthipeptides are a major subset of RiPPs. Through genome mining we identified a novel lanthipeptide biosynthetic gene cluster (lah) from Lachnospiraceae bacterium C6A11, an anaerobic bacterium that is a member of the human microbiota and which is implicated in the development of host disease states such as type 2 diabetes and resistance to Clostridium difficile colonization.

CTP:phosphocholine cytidylyltransferase 1 is phosphorylated and inhibited by sucrose nonfermenting 1-related protein kinase 1 (SnRK1).

phosphatidylcholine (PC) biosynthesis via the Kennedy pathway involves highly endergonic biochemical reactions that must be fine-tuned with energy homeostasis. Previous studies have shown that CTP:phosphocholine cytidylyltransferase (CCT) is an important regulatory enzyme in this pathway and that its activity can be controlled at both transcriptional and posttranslational levels. Here we identified an important additional mechanism regulating plant CCT1 activity.

Insights into the draft genome sequence of bioactives-producing DNG9 isolated from Algerian soil-oil slough.

is widely used as a bioinsecticide due to its ability to form parasporal crystals containing proteinaceous toxins. It is a member of the sensu , a group with low genetic diversity but produces several promising antimicrobial compounds. DNG9, isolated from an oil-contaminated slough in Algeria, has strong antibacterial, antifungal and biosurfactant properties.

The expanding structural variety among bacteriocins from Gram-positive bacteria.

Bacteria use various strategies to compete in an ecological niche, including the production of bacteriocins. Bacteriocins are ribosomally synthesized antibacterial peptides, and it has been postulated that the majority of Gram-positive bacteria produce one or more of these natural products. Bacteriocins can be used in food preservation and are also considered as potential alternatives to antibiotics.

Draft Genome Sequence of Bacillus paralicheniformis F47, Isolated from an Algerian Salty Lake.

F47 was isolated from a salty lake in Ain Baida-Ouargla, southern Algeria. The genome contains genes for the production of several bioactive secondary metabolites, including the siderophore bacillibactin, the lipopeptides fengycin, surfactin, and lichenysin, the antibiotics bacitracin and kanosamine, and a putative circular bacteriocin.

Bacillus amyloliquefaciens ssp. plantarum F11 isolated from Algerian salty lake as a source of biosurfactants and bioactive lipopeptides.

In this study, we identified a new Bacillus strain isolated from an Algerian salty lake that produces metabolites that are active against Gram-positive and Gram-negative bacteria, as well as fungal pathogens. The draft genome sequence of the strain is presented herein. Genome sequence analysis identified the strain to be B.

Draft Genome Sequence of 49, a Potential Probiotic That Produces Multiple Bacteriocins.

49, isolated from dog feces, is active against , vancomycin-resistant enterococci, and Its draft genome sequence reported herein contains a gene cluster encoding multiple bacteriocins and indicates the absence of genes for virulence factors. These characteristics signify the strain's potential for use as a probiotic.

Diacylglycerol Acyltransferase 1 Is Regulated by Its N-Terminal Domain in Response to Allosteric Effectors.

Diacylglycerol acyltransferase 1 (DGAT1) is an integral membrane enzyme catalyzing the final and committed step in the acyl-coenzyme A (CoA)-dependent biosynthesis of triacylglycerol (TAG). The biochemical regulation of TAG assembly remains one of the least understood areas of primary metabolism to date. Here, we report that the hydrophilic N-terminal domain of DGAT1 (BnaDGAT1) regulates activity based on acyl-CoA/CoA levels.

Draft Genome Sequences of E41 and F34 Isolated from Algerian Salt Lakes.

Two strains of , E41 and F34, were isolated from a salt lake in Aïn M'lila-Oum El Bouaghi, eastern Algeria, and Ain Baida-Ouargla, southern Algeria, respectively. Their genomes display genes for the production of several bioactive secondary metabolites, including polyhydroxyalkanoate, iron siderophores, lipopeptides, and bacteriocins.

Identification and three-dimensional structure of carnobacteriocin XY, a class IIb bacteriocin produced by Carnobacteria.

In this study, we report that CbnX (33 residues) and CbnY (29 residues) comprise a class IIb (two-component) bacteriocin in Carnobacteria. Individually, CbnX and CbnY are inactive, but together act synergistically to exert a narrow spectrum of activity. The structures of CbnX and CbnY in structure-inducing conditions were determined and strongly resemble other class IIb bacteriocins (i.

Antimicrobial lipopeptide tridecaptin A1 selectively binds to Gram-negative lipid II.

Tridecaptin A (TriA) is a nonribosomal lipopeptide with selective antimicrobial activity against Gram-negative bacteria. Here we show that TriA exerts its bactericidal effect by binding to the bacterial cell-wall precursor lipid II on the inner membrane, disrupting the proton motive force. Biochemical and biophysical assays show that binding to the Gram-negative variant of lipid II is required for membrane disruption and that only the proton gradient is dispersed.

Solution Structures of Phenol-Soluble Modulins α1, α3, and β2, Virulence Factors from Staphylococcus aureus.

Phenol-soluble modulins (PSMs) are peptide virulence factors produced by staphylococci. These peptides contribute to the overall pathogenicity of these bacteria, eliciting multiple immune responses from host cells. Many of the α-type PSMs exhibit cytolytic properties and are able to lyse particular eukaryotic cells, including erythrocytes, neutrophils, and leukocytes.

Nuclear Magnetic Resonance Solution Structures of Lacticin Q and Aureocin A53 Reveal a Structural Motif Conserved among Leaderless Bacteriocins with Broad-Spectrum Activity.

Lacticin Q (LnqQ) and aureocin A53 (AucA) are leaderless bacteriocins from Lactococcus lactis QU5 and Staphylococcus aureus A53, respectively. These bacteriocins are characterized by the absence of an N-terminal leader sequence and are active against a broad range of Gram-positive bacteria. LnqQ and AucA consist of 53 and 51 amino acids, respectively, and have 47% identical sequences.

Solution structure of acidocin B, a circular bacteriocin produced by Lactobacillus acidophilus M46.

Acidocin B, a bacteriocin produced by Lactobacillus acidophilus M46, was originally reported to be a linear peptide composed of 59 amino acid residues. However, its high sequence similarity to gassericin A, a circular bacteriocin from Lactobacillus gasseri LA39, suggested that acidocin B might be circular as well. Acidocin B was purified from culture supernatant by a series of hydrophobic interaction chromatographic steps.