Organic Synthesis and Theoretical Basicity Calculations of Oligopeptides

Lead Author Major

Medicinal Chemistry

Second Author Major

Biology & Pre-Dentistry

Format

Oral Presentation

Faculty Mentor Name

Jianhua Ren

Faculty Mentor Department

Chemistry

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 amino acid residues on different positions within a peptide of various lengths. A pair of peptides with different sequences of lysine and alanine, such as Ac-Lys-Ala3 and Ac-Ala3-Lys, was 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 was verified by Mass Spectrometry analysis. The three-dimensional structures of the peptides were examined through molecular modeling. Using various computational programs, a large number of conformations were examined and the most stable conformers were collected and their energies were calculated. Theoretical basicities were calculated from these lowest energy conformers. Preliminary data show that a positive charge on the lysine residue influences the intrinsic conformation of the oligopeptide. Furthermore, the conformation influences the basicity as seen with the theoretical calculations. Ultimately changes in basicity result in structural and functional differences of proteins in biological organisms.

Location

DeRosa University Center, Room 211A/B

Start Date

21-4-2011 5:00 PM

End Date

21-4-2011 8:00 PM

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Apr 21st, 5:00 PM Apr 21st, 8:00 PM

Organic Synthesis and Theoretical Basicity Calculations of Oligopeptides

DeRosa University Center, Room 211A/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 amino acid residues on different positions within a peptide of various lengths. A pair of peptides with different sequences of lysine and alanine, such as Ac-Lys-Ala3 and Ac-Ala3-Lys, was 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 was verified by Mass Spectrometry analysis. The three-dimensional structures of the peptides were examined through molecular modeling. Using various computational programs, a large number of conformations were examined and the most stable conformers were collected and their energies were calculated. Theoretical basicities were calculated from these lowest energy conformers. Preliminary data show that a positive charge on the lysine residue influences the intrinsic conformation of the oligopeptide. Furthermore, the conformation influences the basicity as seen with the theoretical calculations. Ultimately changes in basicity result in structural and functional differences of proteins in biological organisms.