solid-phase peptide synthesis haloduracin total synthesis phase - solid-phase-peptide-synthesis-mersacidin-synthesis phase

is-egf-a-steroid-or-peptide-hormone The total synthesis of haloduracin, a two-component lantibiotic, represents a significant challenge and achievement in peptide chemistry.作者：GN Thibodeaux·2015·被引用次数：33—Haloduracinis a lantibiotic that is composed of two post-translationally modifiedpeptides, Halα and Halβ, which are biosynthesized from the precursorpeptides... This complex antimicrobial peptide, identified in *Bacillus halodurans*, comprises two distinct post-translationally modified peptides, Halα and Halβ. Achieving its complete synthesis often relies on advanced techniques such as solid-phase peptide synthesis (SPPS), a cornerstone methodology for constructing peptides of varying complexity.The resin is drawn as a carbocation and the amino acid is drawn as a carboxylate to ease explanation of chemistry. 1. Weigh out appropriate amount of resin. The intricate structure of haloduracin, including its lanthionine cross-links and other modifications, necessitates careful planning and execution of synthetic strategies to mimic its natural formation and function.

Understanding Haloduracin and Its Components

Haloduracin is classified as a lantibiotic, a group of ribosomally synthesized peptides characterized by the presence of the unusual amino acid lanthionine. This class of peptides often exhibits potent antimicrobial activity. Haloduracin itself is composed of two precursor peptides, HalA1 and HalA2, which are processed and modified to yield the mature Halα and Halβ peptides. The biosynthesis involves complex enzymatic machinery, including lanthionine synthetases like HalM. The structural intricacies of these peptides, particularly the thioether bridges formed between cysteine residues, pose substantial hurdles for chemical synthesis.

Solid-Phase Peptide Synthesis for Complex Peptides

Solid-phase peptide synthesis (SPPS) has emerged as the dominant method for producing synthetic peptides, largely due to its efficiency and amenability to automation. The Fmoc/tBu strategy is a widely adopted approach within SPPS, involving the use of a fluorenylmethyloxycarbonyl (Fmoc) protecting group for the α-amino terminus and tert-butyl-based protecting groups for side chainsThe purpose of this guide is to provide practical information for planning and executing successfulsolid phase peptidesyntheses.. This method allows for the stepwise elongation of a peptide chain while it is anchored to an insoluble solid support (resin).

The application of SPPS to the total synthesis of complex peptides like haloduracin involves several critical steps:

* Resin Preparation and First Amino Acid Coupling: The synthesis begins by attaching the C-terminal amino acid to a suitable resin. The choice of resin and linker is crucial for efficient cleavage and protection of the C-terminus.

* Deprotection: The Fmoc group protecting the N-terminus of the growing peptide chain is removed, typically using a mild base such as piperidine.

* Coupling: The next protected amino acid is activated and coupled to the free N-terminus of the resin-bound peptide. Various coupling reagents are employed to ensure high efficiency and minimize racemization.

* Washing: After each deprotection and coupling step, the resin is thoroughly washed to remove excess reagents and byproducts, a key advantage of SPPS that simplifies purification.

* Side Chain Modifications and Cyclizations: For peptides like haloduracin, incorporating post-translational modifications, such as the formation of lanthionine rings, is a significant challenge. These modifications may be introduced during or after the assembly of the linear peptide chain, often requiring specific reagents and reaction conditions.The research details thetotal synthesis of the lantibiotic lactocin S, a natural peptide from Lactobacillus sakei, through solid-phase peptide cyclizations ... Strategies for forming thioether rings, which are characteristic of lantibiotics, are vital.

* Cleavage and Deprotection: Once the full-length peptide is assembled and modified on the resin, it is cleaved from the support, and all remaining side-chain protecting groups are removed simultaneously using a strong acid cocktail (e.g作者：H Liu·2010·被引用次数：1—The preliminary biological evaluation suggests that the oxygen analogue (45) displays the inherent activity of the parentpeptide, but lacks the synergistic ...., trifluoroacetic acid).

* Purification and Characterization: The crude peptide is then purified, typically by reverse-phase high-performance liquid chromatography (RP-HPLC), and its identity and purity are confirmed using mass spectrometry and other analytical techniques.

Challenges and Advancements in Haloduracin Synthesis

The total synthesis of haloduracin is complicated by the presence of multiple thioether cross-links, the stereochemistry of modified amino acids, and the potential for side reactionsInsights into the Mode of Action of the Two-Peptide Lantibiotic .... Researchers have explored various synthetic routes to overcome these challenges2025年8月9日—Additionally, lantibiotics can be produced throughsolid-phase peptide synthesis(SPPS) using orthogonally protected lanthionine rings (31, 33).. For instance, strategies involving the solid-phase synthesis of sulfamidate-containing peptides followed by late-stage intramolecular cyclization have been investigated for similar complex peptide structures.

Comparisons with the synthesis of other lantibiotics, such as lacticin 3147 A2 or lactocin S, provide valuable insights.作者：GN Thibodeaux·2015·被引用次数：33—Haloduracinis a lantibiotic that is composed of two post-translationally modifiedpeptides, Halα and Halβ, which are biosynthesized from the precursorpeptides... Analogues of lacticin 3147 A2 have been synthesized using SPPS and compared to the natural peptide, demonstrating the utility of SPPS in exploring structure-activity relationships. The synthesis of lactocin S has also been achieved through solid-phase peptide cyclizations, highlighting the adaptability of SPPS for diverse lantibiotic structures.Insights into the Mode of Action of the Two-Peptide Lantibiotic ...

The development of novel methodologies, including approaches for fluorescent labeling of peptide termini and the synthesis of peptide analogs with enhanced oxidative stability by removing susceptible sulfur atoms, further advances the field. These innovations not only facilitate the study of native peptides like haloduracin but also open avenues for designing new peptide-based therapeutics with improved properties. The ongoing research in this area underscores the power of chemical synthesis, particularly SPPS, in dissecting the structure, function, and potential applications of complex natural products.Synthesis Notes