Fmoc-Arg(Pbf)-OH

Loading and coupling of Rink Amide resin^[1]:

1. Rink Amide HL (0.98mmol/g) is expanded at 70°C for 20 minutes.

2. 20% piperidine solution is added in DMF to remove the Fmoc groups from the resin.

3. Fmoc amino acids (4.00eq.) are coupled with O-(benzotriazol-1-yl)-N,N,N′,N′-tetrafluorophosphorodimethylurea (HBTU, 3.92eq.), 1-hydroxybenzotriazole hydrate (HOBt, 4.00eq.), and N,N-dipropylacetamide (DIPEA, 8.0eq.).

4. Before coupling the next amino acid, the N-terminal Fmoc is removed with piperidine (20%) in DMF.

5. Fmoc-Phe-OH (4.0eq.) and Fmoc-Trp(Boc)-OH (4.0eq.) are coupled at 70°C for 5 minutes, Fmoc-Bip-OH (4.0eq.) is coupled at 75°C. Fmoc-Arg(Pbf)-OH (4.0eq.) is coupled at room temperature for 60 minutes, and Fmoc-Lys(N3) is coupled at room temperature for 16 hours. N3-PEG200-COOH (4.0eq.) or N3-PEG400-COOH (4.0eq.) is coupled with HBTU (3.92eq.) and HOBt (4.0eq.) for 16 hours at room temperature.

6. After the final coupling, the non-PEGylated peptide is removed from the Fmoc groups, the resin is washed with MeOH and DCM, and then placed in a drying machine overnight.

This protocol only provides a guideline, and should be modified according to your specific needs

References:
[1] Karlsen, E.A.; Stensen, W.; Juskewitz, E.; Svenson, J.; Berglin, M.; Svendsen, J.S.M. Anti-Colonization Effect of Au Surfaces with Self-Assembled Molecular Monolayers Functionalized with Antimicrobial Peptides on S. epidermidis. Antibiotics 2021, 10, 1516.