Peptide oligomers from ultra-short peptides using sortase

Area of Science:

• Biochemistry
• Peptide Chemistry
• Enzymology

Background:

• Sortase A is a bacterial enzyme known for catalyzing peptide bond formation.
• Peptide ligation can produce linear or cyclic structures depending on reaction conditions and peptide length.
• Understanding the behavior of ultra-short peptides in enzymatic ligation is crucial for peptide-based therapeutics and materials.

Purpose of the Study:

• To investigate the outcome of Sortase A catalyzed ligation on ultra-short peptides (<15 amino acids).
• To determine the influence of peptide length and reaction time on the formation of linear versus cyclic peptide oligomers.
• To assess the stability of peptide oligomers formed from peptides containing aminoglycine residues.

Main Methods:

• Enzymatic ligation using Sortase A.
• Synthesis and characterization of ultra-short peptides.
• Analysis of reaction products using techniques like mass spectrometry and HPLC.
• Hydrolysis studies on resulting peptide oligomers.

Main Results:

• Sortase A catalyzed both inter- and intra-molecular transpeptidation, forming linear and cyclic oligomers.
• For peptides >15 amino acids, cyclic peptides were the primary products.
• For ultra-short peptides (<15 amino acids), cyclic oligomers became predominant under prolonged reaction conditions.
• Peptides with 1-3 aminoglycine residues showed similar ligation activity.
• Oligomers derived from peptides with multiple aminoglycine residues exhibited increased susceptibility to hydrolysis.

Conclusions:

• Sortase A can efficiently produce cyclic peptides from ultra-short sequences, especially with extended reaction times.
• The presence of multiple aminoglycine residues in peptides can lead to hydrolytically unstable oligomers.
• These findings have implications for designing stable peptide-based biomaterials and drugs using Sortase A ligation.