Solid-Phase Peptide Synthesis of d-Amino Acids
Poster Number
12A
Research or Creativity Area
Health Sciences
Abstract
Introduction:
Peptides are chains consisting of amino acids linked together by peptide bonds. There are about 20 standard amino acids that make up proteins. Amino acids (except glycine) are found naturally in two configurations: L- amino acids and D- amino acids. D-forms are mirror images of L-forms of amino acids. Some D-amino acids are found in bacterial cell walls while it is also naturally found in the brain, where it is responsible for important signaling molecules that affect the central nervous system. In medical applications, D-amino acids are used as biomarkers for disease diagnosis, and monitoring treatment.
Method:
Solid-phase peptide synthesis starts with putting rink amide resin into a solid-phase peptide synthesis (SPPS) vessel. The purpose of the rink amide resin is to add amino acids. Next, the initial deprotection is conducted; this step includes 20% piperidine in DMF. Then, the coupling step is completed where the amino acid, along with HBTU, DMF, and DIPEA, is agitated in the SPPS vessel. The deprotection and coupling steps are repeated for the addition of each amino acid. The deprotection steps remove the protecting FMOC group which ensures that the amino acid is added to the right place. In between every deprotection and coupling step, the wash steps of MEOH, DCM. MEOH, DCM, and DMF are completed. Once the deprotection and coupling steps are all done, cleavage is conducted. In cleavage, phenol, water, tips, and TFA are mixed in the SPPS vessel. This removes the peptide from the resin. Lastly, the peptide is purified. Cold diethyl ether is used to remove any impurities before it is freeze-dried in liquid nitrogen and then put on the lyophilizer to sublimate.
Conclusion:
The resulting peptides were dCA3 and A3dC. Using solid phase peptide synthesis, the MS/MS spectra support the proposed fragmentation mechanism in which B and Y ions are generated where there were more Y ions that were generated than B ions. The presence of the acetyl group enhances ionization visualization in peptides. The N-terminal acetylation promotes Y ion formation which supports the acetyl group to participate in oxazolone ring formation. The fragmentation mechanism is responsible for producing Y ions in high intensity which needs further investigation to determine whether the position of the basic residue influences fragment ions that were displayed.
Location
Don and Karen DeRosa University Center (DUC) Poster Hall
Start Date
27-4-2024 10:30 AM
End Date
27-4-2024 12:30 PM
Solid-Phase Peptide Synthesis of d-Amino Acids
Don and Karen DeRosa University Center (DUC) Poster Hall
Introduction:
Peptides are chains consisting of amino acids linked together by peptide bonds. There are about 20 standard amino acids that make up proteins. Amino acids (except glycine) are found naturally in two configurations: L- amino acids and D- amino acids. D-forms are mirror images of L-forms of amino acids. Some D-amino acids are found in bacterial cell walls while it is also naturally found in the brain, where it is responsible for important signaling molecules that affect the central nervous system. In medical applications, D-amino acids are used as biomarkers for disease diagnosis, and monitoring treatment.
Method:
Solid-phase peptide synthesis starts with putting rink amide resin into a solid-phase peptide synthesis (SPPS) vessel. The purpose of the rink amide resin is to add amino acids. Next, the initial deprotection is conducted; this step includes 20% piperidine in DMF. Then, the coupling step is completed where the amino acid, along with HBTU, DMF, and DIPEA, is agitated in the SPPS vessel. The deprotection and coupling steps are repeated for the addition of each amino acid. The deprotection steps remove the protecting FMOC group which ensures that the amino acid is added to the right place. In between every deprotection and coupling step, the wash steps of MEOH, DCM. MEOH, DCM, and DMF are completed. Once the deprotection and coupling steps are all done, cleavage is conducted. In cleavage, phenol, water, tips, and TFA are mixed in the SPPS vessel. This removes the peptide from the resin. Lastly, the peptide is purified. Cold diethyl ether is used to remove any impurities before it is freeze-dried in liquid nitrogen and then put on the lyophilizer to sublimate.
Conclusion:
The resulting peptides were dCA3 and A3dC. Using solid phase peptide synthesis, the MS/MS spectra support the proposed fragmentation mechanism in which B and Y ions are generated where there were more Y ions that were generated than B ions. The presence of the acetyl group enhances ionization visualization in peptides. The N-terminal acetylation promotes Y ion formation which supports the acetyl group to participate in oxazolone ring formation. The fragmentation mechanism is responsible for producing Y ions in high intensity which needs further investigation to determine whether the position of the basic residue influences fragment ions that were displayed.
