Bio‐Inspired Design and Potential Biomedical Applications of a Novel Class of High‐Affinity Peptides

Antimicrobial activity and membrane-active mechanism of tryptophan zipper-like β-hairpin antimicrobial peptides

“…The small size and remarkable stability of trpzip peptides make them very attractive as templates for the design of bioactive molecules. To date, some studies have described the development of functional peptides based on the trpzip scaffold, including nucleotide receptors, rubredoxin mimics, peptide ligands, and inhibitors of amyloid formation (Butterfield and Waters 2003;Hopping et al 2013;Kim et al 2012;Nanda et al 2005). However, the biological activities of designed β-hairpin antimicrobial peptides with trpzip motifs have not been studied.…”

Fibronectin extra domain B-specific aptide conjugated nanoparticles for targeted cancer imaging

“…However, a distinct drawback of such peptide ligands is low binding affinity for targets. Very recently, we developed a novel class of high-affinity peptides, termed 'aptides,' that exhibit high affinity -in the 10-to-100 nanomolar range -for a variety of protein targets [25]. Extending this concept to cancer imaging, cancer biomarker-specific aptides conjugated to SPION imaging probes could be suitable candidates for cancer-targeted contrast agents.…”

“…Using phage display-based screening of aptide libraries, we recently identified an aptide, referred to as APT EDB , that exhibits high specificity and affinity for EDB [25]. Here, we report the development of an EDB-specific-aptide-conjugated SPION (APT EDB -SPION) for use in targeted cancer imaging with MRI, describing its synthesis and characterization, ability to bind EDB-expressing cancer cells in vitro, and potential for use in EDB-specific imaging in an in vivo model.…”

Engineering protein modules for diagnostic applications

“…Inspired by the antibody-like structure of the basic leucine zipper protein, a new generation of artificial peptide-scaffolds called aptamer-like peptides or aptides was recently reported. These aptides contain a stabilizing tryptophan zipper scaffold flanked by two randomized ligand-binding regions, resulting in a unique Y-shaped scissors grip structure [30 ] (Figure 2c(ii)). High-affinity aptides can be isolated for a wide range of targets by using phage display.…”

“…The Y-shaped structure of aptides is essential for target recognition as binding is completely abolished by deletion of one of the ligand binding regions or by replacement of four tryptophan residues in the stabilizing scaffold. Owing to its small size (26 amino acids), the lack of disulfide bonds, and modularity, aptides can be easily adopted as the input module for any diagnostic application [30 ].…”