Mild orthogonal solid-phase peptide synthesis.
A Three-Dimensional Orthogonal Protection Scheme for Solid-Phase Peptide Synthesis under Mild Conditions.
Cysteine Protection in Solid-Phase Peptide Synthesis.
Our original hope was that there would be a large reactivity difference between Cys(Mob) and Cys(Acm) derivatives with DTNP. Although the data in seems to suggest a modest reactivity gap, we could not selectively remove a Mob group from cysteine in the presence of a Cys(Acm) derivative using DTNP (data not shown). Hoping to increase the reactivity gap between the two derivatives, we tested the ability of 2,2′-dithiodipyridine (DTP) as a deprotection reagent to further exploit differences in reactivity between Cys(Mob) and Cys(Acm) residues. DTP should be much less reactive as it lacks a nitro group in the para position and hence the disulfide bond of DTP should be much less electrophilic. The results show that DTP also causes deprotection of Cys(Mob) and Cys(Acm) derivatives, but its reaction with Cys(Acm) is much more sluggish than that of a Cys(Mob) derivative as shown in . Using DTP as the deprotectant, the Mob group could be removed using > 6 equivalents of DTP, while only ~40% deprotection was achieved with 15 equivalents of DTP with the Cys(Acm) derivative. The reaction of DTP with either Cys(Mob) or Cys(Acm) results in the formation of a mixed disulfide bond between the thiopyridyl group and the sulfur of cysteine, similar to that of the 5-Npys derivative that is formed when using DTNP. The data in shows that there is a much larger reactivity gap between the two derivatives when using DTP. However, we were not able to achieve orthogonal deprotection of Cys(Mob) and Cys(Acm) residues using DTP in the case of at least one test peptide [AC(Acm)GTTGC(Mob)A].
AB - Application of N-cyclohexyloxocarbonyl (Choc) protection in Boc chemistry on solid phase provides a new possibility for the preparation of protected peptide fragments. A Choc/OcHex protection scheme allows also the assembly of cyclic lactam peptides linked to the resin through the C- terminus. Choc protection is stable under the 1M TMSOTf-thioanisole/TFA cleavage condition at 0°C, but it is removable by anhydrous HF. We have utilized cyclohexyloxycarbonyl as an orthogonal protecting group for the synthesis of a i) bicyclic epitope peptide of glycoprotein D of HSV 1 on BHA resin and ii) fully protected hexapeptide involved in protein transport on Merrifield resin.
Orthogonal Solid-Phase Synthesis of Bicyclic Peptides.
This week is all about cyclizations by means of cysteine disulfide bonds. Cyclizations are often performed via a disulfide bond between two cysteine sulfhydryl groups, called folding. Some peptides fold by natural oxidation, while some require a synthesis strategy to achieve the correct conformation. If native folding does not occur in peptides with more than two cysteines, you can turn to an orthogonal protection strategy, where various protecting groups are used that require differing cleavage conditions. You selectively remove the groups based on where you want the disulfide bonds to occur. As you increase the number of cysteines, you increase the difficulty of the synthesis. Many peptide toxins contain multiple disulfide bonds and are considered . Other examples include the and .
There are two majorly used forms of SPPS - Fmoc and Boc. Unlike ribosome protein synthesis, solid-phase peptide synthesis proceeds in a C-terminal to N-terminal fashion. The N-termini of amino acid monomers is protected by these two groups and added onto a deprotected amino acid chain.
What means orthogonal in peptide synthesis?
Novel -Xanthenyl Protecting Groups for Cysteine and Their Applications for the α-9-Fluorenylmethyloxycarbonyl (Fmoc) Strategy of Peptide Synthesis.
Backbone Amide Linker (BAL) Strategy for α-9-Fluorenylmethoxycarbonyl (Fmoc) Solid-Phase Synthesis of Unprotected Peptide -Nitroanilides and Thioesters.
Orthogonal ligation of unprotected peptide segments ..
disrupting protection technique in peptide synthesis
A Novel, Convenient, Three-Dimensional Orthogonal Strategy for Solid-Phase Synthesis of Cyclic Peptides.
Protective Groups for Peptide Synthesis
Synthesis of 2-Acetamido-2-deoxy-β-D-glucopyranose -Glycopeptides from -Dithiasuccinoyl-Protected Derivatives.
Protection for Solid-Phase Peptide Synthesis
Novel cysteine protecting groups for the α-9-fluorenylmethyloxycarbonyl (Fmoc) strategy of peptide synthesis.
Journal of Nanoscience and Nanotechnology
-2,4,6-Trimethoxybenzyl (Tmob): A Novel Cysteine Protecting Group for the α-9-Fluorenylmethyloxycarbonyl (Fmoc) Strategy of Peptide Synthesis.
Goji Berry - Wolfberry - buy Lycium Barbarum - Ray …
A New Fluoridolyzable Anchoring Linkage for Orthogonal Solid-Phase Peptide Synthesis: Design, Preparation, and Application of the -(3 or 4)-[[4-(Hydroxymethyl)phenoxy]--butylphenylsilyl]phenyl Pentanedioic Acid, Monoamide (Pbs) Handle.
Strategies for Preparing Albumin-based Nanoparticles …
Mild, orthogonal solid-phase peptide synthesis: use of α-dithiasuccinoyl (Dts) amino acids and -(-propyldithio)carbonylproline, together with -alkoxybenzyl ester anchoring linkages.
Submitted Abstracts | College of Physical and …
Synthesis of α-Conotoxin SI, a Bicyclic Tridecapeptide Amide with Two Disulfide Bridges: Illustration of Novel Protection Schemes and Oxidation Strategies.
Program | 6th World Congress and Expo on …
Before the Fmoc group became popular, the t-Boc group was commonly used for protecting the terminal amine of the peptide, requiring the use of more acid stable groups for side chain protection in orthogonal strategies. Boc groups can be added to amino acids with Di-tert-butyl dicarbonate (Boc anhydride) and a suitable base.
View session wise speaker sessions below
Novel ω-Xanthenyl Protecting Groups for Asparagine and Glutamine, and Applications to α-9-Fluorenylmethyloxycarbonyl (Fmoc) Solid-Phase Peptide Synthesis.
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