Complementary DNA display selection of high-affinity peptides binding the vacuolating toxin (VacA) ofHelicobacter pylori

Abstract

Artificial peptides designed for molecular recognition of a bacterial toxin have been developed. Vacuolating cytotoxin A protein (VacA) is a major virulence factor of Helicobacter pylori, a gram-negative microaerophilic bacterium inhabiting the upper gastrointestinal tract, particularly the stomach. This study attempted to identify specific peptide sequences with high affinity for VacA using systematic directed evolution in vitro, a cDNA display method. A surface plasmon resonance-based biosensor and fluorescence correlation spectroscopy to examine binding of peptides with VacA identified a peptide (GRVNQRL) with high affinity. Cyclization of the peptide by attaching cysteine residues to both termini improved its binding affinity to VacA, with a dissociation constant (Kd ) of 58 nm. This study describes a new strategy for the development of artificial functional peptides, which are promising materials in biochemical analyses and medical applications.

Evolving a Peptide: Library Platforms and Diversification Strategies

“…Finally, the library is released from the solid support by restrictase treatment [161]. This refined platform has been used in screening for cysteine-rich peptides with antagonistic activity at interleukin-6-receptor [162], peptide antagonists of growth hormone secretagogue receptor [163], amino group binders [164], binders of vacuolating toxin [165], and peptide agonist and antagonist of angiotensin II type-1 receptor [166]. The problem of RNA instability instigated the design of another DNA-based approach called CIS display.…”