title: QCM-D analysis of binding mechanism of phage particles displaying a constrained heptapeptide with specific affinity to SiO2 and TiO2.
abstract: A growing number of peptides capable of specifically recognizing inorganic materials have been reported, incrementally increasing the potential to harness peptides as a biological linker to bridge biomolecules and inorganic materials at nanometer scale. In this study, we identified disulfide bond constrained heptapeptides with specific binding affinity to SiO2 and TiO2 using a phage display technique. Interestingly, two of the phage surface displayed peptides enriched with basic amino acid residues, STB1 (HKKPSKS) and STB2 (TKRNNKR), showed a cross binding affinity to both metal oxides. To understand the underlying binding mechanism, binding behaviors of phage particles harboring the STB1 (a high-frequency heptapeptide exhibiting dual binding affinity to both metal oxides) were investigated in a wide pH range using quartz crystal microbalance with energy dissipation measurement (QCM-D). It was found that the binding of STB1-harboring phages to the two metal oxides was clearly mediated by the peptide moiety displayed on the phage surface in a pH-dependent manner, indicating that the binding is largely governed by electrostatic interaction. Furthermore, the interpretation of QCM-D signals (i.e., frequency shift and dissipation shift), with the aid of AFM image analysis of the phage particles bound on the surface of the two metal oxides, elucidated whether the nature of phage (or the displayed peptide) binding to the metal oxides is largely specific or nonspecific.
authors.affiliation: Department of Chemical & Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
authors.forename: Haibin
authors.initials: H
authors.lastname: Chen
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Su
authors.forename: Koon-Gee
authors.initials: KG
authors.lastname: Neoh
authors.forename: Woo-Seok
authors.initials: WS
authors.lastname: Choe
mesh_terms: D000595:Amino Acid Sequence; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification; D010087:Oxides / Q000737:chemistry; D019151:Peptide Library; D012822:Silicon Dioxide / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D009842:Oligopeptides; D010087:Oxides; D019151:Peptide Library; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium