1. Setup
2. Loading First Bis-Peptide Onto Resin
3. Deprotection of First Bis-Peptide and Simultaneous Resin Capping
4. Coupling Boc/tBu-Protected Functionalized Bis-Amino Acid
5. Deprotection of Boc/tBu-Protected Functionalized Bis-Amino Acid
6. Repeat steps 4 and 5 as desired to synthesize targeted bis-peptide.
7. Functionalizing the Bis-Peptide Prolidine End
8. Deprotection of Fmoc and Acylation of the Quaternary End of the Bis-Peptide
9. Remove the Boc Group from the Resin Bound Amino Acid and Cleave from Resin
10. Purification of Bis-Peptide
11. Assessment Methods
12. Representative Results
An example of both crude (Figure 4) and purified (Figure 5) LCMS traces are provided. Purified yields of approximately 10% are expected using the methods outlined above.
Figure 1. Diagram of Experimental Set-Up for Solid Phase Synthesis.
Figure 2. Relevant Nomenclature of Bis-Amino Acids/Bis-Peptides.
Figure 3. Overall Synthetic Scheme. Click here to view larger figure.
Figure 4a. HPLC Trace of Crude Product at 274 nm.
Figure 4b. MS Spectrum of Crude Product Peak.
Figure 5a. HPLC Trace of Purified Product at 274 nm.
Figure 5b. MS Spectrum of Purified Product Peak.
Name | Company | Catalogue Number | Comments |
HMBA-Am Resin | NovaBiochem | 855018 | |
MSNT | NovaBiochem | 851011 | |
NMI | Sigma-Aldrich | 336092 | Toxic, Corrosive |
DCM | Sigma-Aldrich | D65100 | Carcinogenic |
Anhydrous DCM | Acros | 34846 | Carcinogenic |
33% Hydrogen Bromide in Acetic Acid | Sigma-Aldrich | 248630 | Toxic, Corrosive, Fumes when open |
DIPEA | Sigma-Aldrich | 387649 | Flammable, Toxic, Corrosive |
DMF | Fisher Scientific | AC27960 | Flammable, Toxic |
Anhydrous DMF | Acros | 34843 | Flammable, Toxic |
HOAt | GenScript | C01568 | |
DIC | Acros | BP590 | Flammable, Toxic, Corrosive |
TFA | Sigma-Aldrich | T6508 | Toxic, Corrosive |
TIPS | Acros | 21492 | Flammable, Toxic |
Piperidine | Sigma-Aldrich | 104094 | Flammable, Toxic, Corrosive |
HATU | GenScript | C01566 | Toxic |
NMP | Acros | 36438 | Toxic |
DMAP | NovaBiochem | 851055 | Toxic |
Methyl Red | Sigma-Aldrich | 250198 | |
THF | Sigma-Aldrich | 401757 | Flammable, Toxic, Peroxide Forming |
Pyrrolidine | Sigma-Aldrich | P73803 | Flammable, Toxic, Corrosive |
Dimethyl Sulfoxide | Fisher | D1281 | |
SPPS Reaction Vessels | Grace | 211108 | |
LCMS | Agilent | 1200 Series | |
Semi-Prep LC | Hewlett Packard | 1100 Series | |
Lyophilizer | Labconco | 7934027 | |
Rotovapor | Buchi | R-210 Series | |
Argon | Airgas | AR PP300CT |
In 1962, R.B. Merrifield published the first procedure using solid-phase peptide synthesis as a novel route to efficiently synthesize peptides. This technique quickly proved advantageous over its solution-phase predecessor in both time and labor. Improvements concerning the nature of solid support, the protecting groups employed and the coupling methods employed over the last five decades have only increased the usefulness of Merrifield’s original system. Today, use of a Boc-based protection and base/nucleophile cleavable resin strategy or Fmoc-based protection and acidic cleavable resin strategy, pioneered by R.C. Sheppard, are most commonly used for the synthesis of peptides1.
Inspired by Merrifield’s solid supported strategy, we have developed a Boc/tert-butyl solid-phase synthesis strategy for the assembly of functionalized bis-peptides2, which is described herein. The use of solid-phase synthesis compared to solution-phase methodology is not only advantageous in both time and labor as described by Merrifield1, but also allows greater ease in the synthesis of bis-peptide libraries. The synthesis that we demonstrate here incorporates a final cleavage stage that uses a two-step “safety catch” mechanism to release the functionalized bis-peptide from the resin by diketopiperazine formation.
Bis-peptides are rigid, spiro-ladder oligomers of bis-amino acids that are able to position functionality in a predictable and designable way, controlled by the type and stereochemistry of the monomeric units and the connectivity between each monomer. Each bis-amino acid is a stereochemically pure, cyclic scaffold that contains two amino acids (a carboxylic acid with an α-amine)3,4. Our laboratory is currently investigating the potential of functional bis-peptides across a wide variety of fields including catalysis, protein-protein interactions and nanomaterials.
In 1962, R.B. Merrifield published the first procedure using solid-phase peptide synthesis as a novel route to efficiently synthesize peptides. This technique quickly proved advantageous over its solution-phase predecessor in both time and labor. Improvements concerning the nature of solid support, the protecting groups employed and the coupling methods employed over the last five decades have only increased the usefulness of Merrifield’s original system. Today, use of a Boc-based protection and base/nucleophile cleavable resin strategy or Fmoc-based protection and acidic cleavable resin strategy, pioneered by R.C. Sheppard, are most commonly used for the synthesis of peptides1.
Inspired by Merrifield’s solid supported strategy, we have developed a Boc/tert-butyl solid-phase synthesis strategy for the assembly of functionalized bis-peptides2, which is described herein. The use of solid-phase synthesis compared to solution-phase methodology is not only advantageous in both time and labor as described by Merrifield1, but also allows greater ease in the synthesis of bis-peptide libraries. The synthesis that we demonstrate here incorporates a final cleavage stage that uses a two-step “safety catch” mechanism to release the functionalized bis-peptide from the resin by diketopiperazine formation.
Bis-peptides are rigid, spiro-ladder oligomers of bis-amino acids that are able to position functionality in a predictable and designable way, controlled by the type and stereochemistry of the monomeric units and the connectivity between each monomer. Each bis-amino acid is a stereochemically pure, cyclic scaffold that contains two amino acids (a carboxylic acid with an α-amine)3,4. Our laboratory is currently investigating the potential of functional bis-peptides across a wide variety of fields including catalysis, protein-protein interactions and nanomaterials.
In 1962, R.B. Merrifield published the first procedure using solid-phase peptide synthesis as a novel route to efficiently synthesize peptides. This technique quickly proved advantageous over its solution-phase predecessor in both time and labor. Improvements concerning the nature of solid support, the protecting groups employed and the coupling methods employed over the last five decades have only increased the usefulness of Merrifield’s original system. Today, use of a Boc-based protection and base/nucleophile cleavable resin strategy or Fmoc-based protection and acidic cleavable resin strategy, pioneered by R.C. Sheppard, are most commonly used for the synthesis of peptides1.
Inspired by Merrifield’s solid supported strategy, we have developed a Boc/tert-butyl solid-phase synthesis strategy for the assembly of functionalized bis-peptides2, which is described herein. The use of solid-phase synthesis compared to solution-phase methodology is not only advantageous in both time and labor as described by Merrifield1, but also allows greater ease in the synthesis of bis-peptide libraries. The synthesis that we demonstrate here incorporates a final cleavage stage that uses a two-step “safety catch” mechanism to release the functionalized bis-peptide from the resin by diketopiperazine formation.
Bis-peptides are rigid, spiro-ladder oligomers of bis-amino acids that are able to position functionality in a predictable and designable way, controlled by the type and stereochemistry of the monomeric units and the connectivity between each monomer. Each bis-amino acid is a stereochemically pure, cyclic scaffold that contains two amino acids (a carboxylic acid with an α-amine)3,4. Our laboratory is currently investigating the potential of functional bis-peptides across a wide variety of fields including catalysis, protein-protein interactions and nanomaterials.