trancend-peptides The total synthesis of haloduracin represents a significant endeavor in the field of peptide chemistry, particularly when employing solid-phase peptide synthesis (SPPS). Haloduracin, a lantibiotic composed of two distinct, post-translationally modified peptides (Halα and Halβ), has garnered attention for its biological activity, which is dependent on the synergistic interaction of these modified components. Achieving the complete synthesis of such complex molecules requires meticulous planning and execution, with SPPS offering a robust platform for building these intricate peptide structures.
Haloduracin was identified in the bacterium *Bacillus halodurans* and belongs to the lantibiotic class, characterized by the presence of lanthionine rings and other thioether cross-links formed through post-translational modifications of precursor peptides. The biological activity of haloduracin is intrinsically linked to the correct formation and interaction of its two mature peptide chains, Halα and Halβ. The biosynthesis of these peptides involves complex enzymatic machinery, such as the HalM enzymes, which catalyze key modifications.作者：S De Luca·被引用次数：13—To prove the feasibility of the procedure, thesynthesisof a thioether ring. B mimetic of the natural lantibiotichaloduracinβ was performed. Understanding these natural pathways often informs and guides synthetic strategies.
Solid-phase peptide synthesis, a cornerstone technique in modern peptide chemistry, provides a practical and efficient method for the assembly of peptides. SPPS involves the sequential addition of amino acids to a growing peptide chain anchored to an insoluble solid support, typically a resin.Insights into the Mode of Action of the Two-Peptide Lantibiotic ... This methodology, pioneered by RBiosynthesis of the Antimicrobial Peptide Epilancin 15X .... Bruce Merrifield, allows for easy separation of reaction byproducts through simple washing steps, simplifying purification and enabling the synthesis of longer and more complex peptides.
For the total synthesis of haloduracin, SPPS offers several advantages:
* Efficiency: The iterative nature of SPPS allows for the automated or manual addition of protected amino acids, building the peptide sequence step-by-step.
* Purification: Intermediate purification is minimized, as excess reagents and byproducts are washed away after each coupling and deprotection step.
* Versatility: SPPS can be adapted to incorporate non-standard amino acids and modifications, which are crucial for synthesizing naturally occurring peptides like haloduracinA General Method for Fluorescent Labeling of the N-Termini of ....
Commonly, Fmoc (9-fluorenylmethyloxycarbonyl) chemistry is employed in SPPS due to its mild deprotection conditions, which are compatible with a wide range of sensitive functional groups and peptide structures. The synthesis of haloduracin peptides, including those with N-terminal modifications or thioether rings, often relies on carefully chosen protecting groups and coupling reagents to ensure regioselectivity and high yields.
The total synthesis of haloduracin presents several unique challenges beyond standard peptide synthesis:
* Post-Translational Modifications: Haloduracin peptides are heavily modified, featuring lanthionine bridges and other thioether linkages. Replicating these modifications synthetically requires specialized reagents and strategic planning. For instance, methods have been developed for the synthesis of thioether rings or the generation of cryptic N-terminal dehydro amino acids, which are precursors to these modifications.
* Stereochemistry: Ensuring the correct stereochemistry at each amino acid residue and during the formation of cross-links is critical for the peptide's final structure and biological activityDiscovery and in vitro biosynthesis of haloduracin, a two- ....
* Peptide Coupling and Cyclization: The formation of the lanthionine rings and other cyclizations requires specific chemical conditions.作者：SC Bobeica·2019·被引用次数：106—ProTide Cl-TCP Cl resin (CEM) was used for thesolid phase peptide synthesis(SPPS) of the ProcA2.8 sequence-based aldehyde inhibitor on a ... Strategies like S-alkylation with substituted thiols or solid-phase synthesis of sulfamidate-containing peptides followed by cyclization have been explored.
* Component Interaction: Since haloduracin's activity depends on both Halα and Halβ, synthesizing both components and ensuring their correct association and fold is paramount.
Researchers have employed various SPPS strategies for the synthesis of haloduracin and related lantibiotics. This often involves:
1.R. Bruce Merrifield Award - American Peptide Society Precursor Peptide Synthesis: Standard Fmoc-based SPPS is used to assemble the linear precursor peptides of Halα and Halβ.
2. Introduction of Modifications: Specialized methods are then applied to introduce the necessary modifications, such as dehydration of serine and threonine residues to form dehydroamino acids, followed by Michael addition of cysteine thiols to form lanthionine rings.作者：NA Bindman·2013·被引用次数：49—The methodology was successfully applied to prochlorosins 1.7 and 2.8, as well as the lantibiotics lacticin 481,haloduracinα, andhaloduracinβ. The ...
3. Cyclization: Intramolecular cyclization reactions are conducted on the solid support or after cleavage from the resin to form the characteristic thioether bridges.Overview of Solid Phase Peptide Synthesis (SPPS)
4.Catalytic promiscuity of a bacterial α-N-methyltransferase Final Deprotection and Purification: After all modifications and couplings are complete, the peptide is cleaved from the resin, and all protecting groups are removed. Extensive purification, often using High-Performance Liquid Chromatography (HPLC), is then required to isolate the pure synthetic haloduracin peptides.
The development of general methods for fluorescent labeling of the N-termini of lanthipeptides, which has been successfully applied to haloduracinα and haloduracinβ, highlights the adaptability of SPPS for creating functionalized analogs. Furthermore, studies on the synthesis of mimetics of natural lantibiotics, such as haloduracinβ, using S-alkylation techniques, demonstrate ongoing innovation in this area.
The successful total synthesis of complex natural products like haloduracin using SPPS not only provides valuable tools for biological research but also opens avenues for developing novel antimicrobial agents. Continued advancements in SPPS techniques, including novel coupling chemistries, improved resin technologies, and more efficient methods for post-translational modification, will undoubtedly facilitate the synthesis of even more intricate and therapeutically relevant peptide structures.(PDF) Synthesis of the Lantibiotic Lactocin S Using Peptide ... The ability to precisely control peptide sequence, structure, and modification through SPPS remains a powerful approach for exploring the vast chemical space of peptides.(PDF) Synthesis of the Lantibiotic Lactocin S Using Peptide ...
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