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Showing 1 to 20 of 23 for “"Lantibiotic"”.
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Exploring and understanding lantibiotic biosynthesis
… found in nature. One such class of RiPPs are the lantibiotics, lanthipeptides with antimicrobial activity. The unifying PTMs found in lanthipeptides are thioether crosslinks, called lanthionine and methyl lanthionine. The crosslinks are formed via the dehydration of serine and threonine residues …
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Mechanistic Investigations of Cyclase Enzymes Involved in Lantibiotic Biosynthesis
Lantibiotics are peptide antibiotics that contain thioether bridges, termed lanthionines, putatively generated by Michael addition of cysteines to dehydrated serine and threonine residues in the pre-lantibiotic peptide. In class AI lantibiotics, the post-translational modifications are proposed to …
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Investigation of the Enzymes Involved in Lantibiotic Biosynthesis: Lacticin 481 and Haloduracin
… peptides is the final step in the maturation of lantibiotics, and is required for achievement of full biological activity. In lacticin 481 maturation, this peptide cleavage reaction is performed by the N-terminal protease domain of the lacticin 481 transporter, LctT. The activity of the protease …
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Mechanistic Studies of Lantibiotic Biosynthetic Enzymes and Discovery of Novel Lanthionine-Containing Peptides
Lantibiotics are ribosomally synthesized antimicrobial peptides containing unique thioether crosslinks, lanthionines and methyllanthionines. These motifs are introduced posttranslationally in a two-step process, which involves the dehydration of serines and threonines into dehydroalanines and …
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Investigations of the Mechanism and Substrate Scope of the Enzymes Involved in Lantibiotic Biosynthesis
… This peptide is the substrate of the putative lantibiotic dehydratase, SpaB, and cyclase SpaC. The heterologously expressed and purified SpaS peptide was employed in assays with the purified SpaB and SpaC proteins to investigate conditions for the in vitro reconstitution of these proteins. The …
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Use of solution-state nuclear magnetic resonance spectroscopy to determine the structures of medicinally relevant peptides and proteins
… all modified to their mature form by a single lantibiotic synthetase. Next was the two peptide lantibiotic cytolysin, unique among bacteriocins in that it has hemolytic activity in addition to bactericidal activity. Nisin, the prototypical lantibiotic, was studied in the context of the immunity …
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Biosynthesis and mode of action of ribosomally synthesized and post-translationally modified antimicrobial peptides
… haloduracin, a recently discovered two-peptide lantibiotic, possesses nanomolar antimicrobial activity against a panel of bacteria strains. The potency of haloduracin rivals that of nisin, an economically and therapeutically relevant lantibiotic, which can be attributed to a similar dual mode of …
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Structural and Biochemical Studies of Nisin *Biosynthesis and Autoimmunity
The lantibiotic nisin is a 34-residue bacteriocin produced by the Gram-positive bacteria Lactococcus lactis spp. It is first ribosomally synthesized as an inactive precursor which is then post-translationally modified into its mature biologically active form. Described herein is a two-part study …
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Investigations of the Substrate Specificity of Lacticin 481 Synthetase and Utilization in Peptide Engineering Applications
… of post-translational modifications in non-lantibiotic peptides fused to the LctA leader peptide. LctM was utilized to efficiently introduce dehydrated, phosphorylated, and lanthionine cross-linked amino acids into therapeutically relevant non-lantibiotic peptides. Furthermore, enzymatically …
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Characterisation of novel bacteriocins from canine sources
… thesis explores the class Ia bacteriocins termed lantibiotics, and the identification and characterisation of novel bacteriocins from canine sources. Chapter 1 focuses on the current knowledge regarding the self-protection mechanisms employed by lantibiotic-producing bacteria via their lantibiotic …
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Biosynthesis of the antimicrobial peptide epilancin 15X
Lantibiotics are polycyclic antimicrobial peptides that are ribosomally synthesized and posttranslationally modified to their biologically active forms. The recently discovered lantibiotic epilancin 15X produced by Staphylococcus epidermidis 15X154 is active against several pathogenic bacteria, …
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Investigations into the roles and molecular mechanisms of LanC-like proteins
… shown by many members of the family (hence named lantibiotics) have drawn the most attention and make them promising antibacterial drug candidates. One of the posttranslational modifications necessary for lanthipeptide synthesis and activity is a Michael-type addition of a cysteinyl thiol to …
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Bioengineering of nisin to enhance functionality against dairy pathogens
… focuses on a specific bacteriocin group, the lantibiotics (Lanthionine-containing antibiotics). Their numerous methods of appliance in a food setting and how their gene-encoded nature can be modified to improve on overall bioactivity and functionality are explored here. The use of a …
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Expanding the structural diversity of the RiPP class of natural products
… amino acid incorporation in the class I lantibiotic nisin and the class II lantibiotic lacticin 481 using amber stop codon technology.
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Investigation of the Lacticin 481 Synthetase and Its Substrate LctA in the Production of the Antibiotic Lacticin 481
Lantibiotics are ribosomally synthesized and post-translationally modified peptide antimicrobial agents produced by Gram-positive bacteria that contain thioether cross-links termed lanthionines. Lantibiotic biosynthesis begins with a precursor peptide (LanA) consisting of leader and propeptide …
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From Peptide Precursors to Lanthionine -Containing Peptide Antibiotics Using the First Isolated and Active Lacticin 481 Synthetase: Mechanistic Studies and Peptide Engineering
… very first in vitro biosynthetic system of any lantibiotic. In addition, upon treatment with the protease Lys-C, the modified peptide in the absence of the leader sequence and the first Lys residue showed biological activity. Mechanistic studies with the active LctM disclosed that the activity …
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An investigation into novel bacteriocin producers isolated for shelf life extension of dairy products
… was found to encode a novel two component lantibiotic. One Streptococcus uberis isolate contained four operons for bacteriocin production, one of which encoded a novel two component lantibiotic. During the screen for bacteriocin producing isolates described in chapter 4, a strain of …
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Bioengineering strategies to improve functional qualities of nisin
… to the subgroup of bacteriocins called the lantibiotics, which contain several unusual amino acids as a consequence of enzyme-mediated post-translational modifications. As nisin is produced by generally regarded as safe (GRAS) microorganisms, it could potentially be applied in a clinical …
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Biosynthesis and engineering of lanthipeptides
… For instance, in vitro reconstitution of the lantibiotic synthetase CinM and the tailoring enzyme CinX allowed for detailed studies of these enzymes as described in Chapter III. On the other hand, through production of cinnamycin in E. coli, the activity of a new enzyme called cinorf7 was …
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