Title

Synthesis and Molecular Modeling of Oligopeptides

Format

Oral Presentation

Abstract/Artist Statement

Peptides are building blocks for enzymes that perform almost all functions in a living organism. The peptide’s shape or conformation is critical to its function. This research project is part of a larger study to evaluate how peptide conformations are influenced by having basic or acid amino acid residues on different positions within a peptide. A group of peptides with different sequences of lysine, diaminopriopionic acid, alanine, and glycine, such as Ac-Lys-Gly3 and Ac- Ala3-Dap, were synthesized. These peptides were synthesized using the solid phase peptide synthesis (SPPS) method. SPPS started with a solid anchor and amino acids are added one by one to build a fully sequenced peptide. The peptide's sequence is verified by Mass Spectrometry analysis. The three-dimensional structures of the peptides were examined through molecular modeling. Using a combination of Spartan and Gaussian computational programs, a large number of conformations were examined and the most stable conformers were collected and their energies were calculated. Proton affinities (PA), a measure of basic strength, were calculated from the most stable conformers. As preliminary data show, lysine-polyglycine peptide, with the basic residue at the beginning, adapts a globular shape. The polyglycine-lysine peptide adapts a more structured helical conformation with the basic residue at the end. This suggests that with a basic residue lysine at the end of the peptide is important for the helical conformation.

Location

DeRosa University Center, Room 211 A/B

Start Date

1-5-2010 9:00 AM

End Date

1-5-2010 12:00 PM

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May 1st, 9:00 AM May 1st, 12:00 PM

Synthesis and Molecular Modeling of Oligopeptides

DeRosa University Center, Room 211 A/B

Peptides are building blocks for enzymes that perform almost all functions in a living organism. The peptide’s shape or conformation is critical to its function. This research project is part of a larger study to evaluate how peptide conformations are influenced by having basic or acid amino acid residues on different positions within a peptide. A group of peptides with different sequences of lysine, diaminopriopionic acid, alanine, and glycine, such as Ac-Lys-Gly3 and Ac- Ala3-Dap, were synthesized. These peptides were synthesized using the solid phase peptide synthesis (SPPS) method. SPPS started with a solid anchor and amino acids are added one by one to build a fully sequenced peptide. The peptide's sequence is verified by Mass Spectrometry analysis. The three-dimensional structures of the peptides were examined through molecular modeling. Using a combination of Spartan and Gaussian computational programs, a large number of conformations were examined and the most stable conformers were collected and their energies were calculated. Proton affinities (PA), a measure of basic strength, were calculated from the most stable conformers. As preliminary data show, lysine-polyglycine peptide, with the basic residue at the beginning, adapts a globular shape. The polyglycine-lysine peptide adapts a more structured helical conformation with the basic residue at the end. This suggests that with a basic residue lysine at the end of the peptide is important for the helical conformation.