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Showing 1 to 20 of 24 for “"Lantibiotics"”.
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Chemical Methods for Studying the Biosynthesis of Lantibiotics and Prostaglandins
Prostaglandin H Synthase (PGHS) converts arachidonic acid (AA) into the first intermediate in the synthesis of prostaglandins via a radical mechanism. Prostaglandins play a number of roles in the body, including the regulation of blood flow to certain organs, controlling transport across membranes, …
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Chemical and chemoenzymatic syntheses of lantibiotics and other bioactive cyclic peptides
New antibiotics are desperately needed to combat the disturbing rise of pathogenic microorganisms resistant to traditional treatments. Throughout the history of modern medicine, natural products have played a leading role as a source and inspiration of new drugs, particularly antibacterial agents. …
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Biochemical characterization of enzymes involved in the post-translational modification of lantibiotics
The student, Manuel Ortega, accepted the attached license on 2015-11-05 at 09:42.
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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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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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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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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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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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New chemical and biosynthetic methodologies for the study of lanthipeptides
… However, the mode of action of only a few lantibiotics has been determined thus far. A general challenge is the availability of a suitable functional group for chemoselective modification. Chapter 4 will discuss novel methodology to introduce an N-terminal ketone into various lanthipeptides …
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Preparation of Dehydropeptides and Their Application in the Convergent Synthesis of Peptide Conjugates
Beyond its utility in the preparation of lantibiotics, this method is also well suited for the preparation of peptide conjugates. The functionalities encountered in natural amino acids include nucleophilic, acidic, and basic groups, but no electrophilic moieties. Thus, introduction of an …
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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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Exploration of the biosynthesis of lanthipeptides
… possess antimicrobial activity, known as lantibiotics with known modes of action including lipid II binding, pore formation, inhibition of spore outgrowth, and phosphatidylethanolamine (PE) binding. Several lanthipeptides display no antimicrobial activities but have other functions …
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Organization of the Streptococcal ExPortal and its Interaction with Cationic Antimicrobial Peptides
… of the ExPortal. Exposure of streptococci to lantibiotics that preferentially bind and sequester lipid II in the cytoplasmic membrane disrupted ExPortal organization and secretory function in a manner similar to CAP activity. Given that both CAPs and lantibiotics target lipid components of the …
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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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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 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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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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Characterization of D-amino acid-containing neuropeptides from metazoa
… the prokaryotes (e.g., bacterial cell wall and lantibiotics) has been considered exceptions to this rule. In the animal kingdom, proteins are thought to be more strictly built in the L-form due to the chiral selectivity of ribosome-based protein synthesis mechanism. However, in recent years it …
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Biomedical applications for bacteriocins in infection and oncology
Lantibiotics are a subclass of a group of bacterially produced antimicrobial peptides called bacteriocins. They are characterized by post-translation modifications resulting in the presence of unusual amino acid residues such as dehydroalanine (Dha), dehydrobutyrine (Dhb) and lanthionine/ …
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DNA catalysts as phosphatases and as phosphoserine lyases
… of several bioactive cyclic peptides such as lantibiotics, thiopeptides and microcystins. DNA enzymes were identified to establish the fundamental catalytic ability to eliminate phosphate from phosphoserine (pSer) to form Dha, namely phosphoserine lyase activity. Furthermore, DhaDz1 was …
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