Isolation of ZnO-Binding 12-mer Peptides and Determination of Their Binding Epitopes by NMR Spectroscopy

Abstract

Inorganic-binding peptides are in the focus of research fields such as materials science, nanotechnology, and biotechnology. Applications concern surface functionalization by the specific coupling to inorganic target substrates, the binding of soluble molecules for sensing applications, or biomineralization approaches for the controlled formation of inorganic materials. The specific molecular recognition of inorganic surfaces by peptides is of major importance for such applications. Zinc oxide (ZnO) is an important semiconductor material which is applied in various devices. In this study the molecular fundamentals for a ZnO-binding epitope was determined. 12-mer peptides, which specifically bind to the zinc- or/and the oxygen-terminated sides of single-crystalline ZnO (0001) and (000-1) substrates, were selected from a random peptide library using the phage display technique. For two ZnO-binding peptides the mandatory amino acid residues, which are of crucial importance for the specific binding were determined with a label-free nuclear magnetic resonance (NMR) approach. NMR spectroscopy allows the identification of pH dependent interaction sites on the atomic level of 12-mer peptides and ZnO nanoparticles. Here, ionic and polar interaction forces were determined. For the oxygen-terminated side the consensus peptide-binding sequence (HSXXH) was predicted in silico and confirmed by the NMR approach.

Thermodynamic Study of Interactions Between ZnO and ZnO Binding Peptides Using Isothermal Titration Calorimetry

“…22 HHGHSPTSPQVR peptide was found to be the stronger binder for the ZnO substrate used. 22 The applications of ITC continue to evolve from conventional biomolecular recognition reactions into diverse areas of interest in the medical/academic fields and industrial sector. An example is the developing use of ITC to study interactions between proteins/peptides and inorganic nanoparticles for biomedical applications.…”

Biomimetic Magnetite Formation: From Biocombinatorial Approaches to Mineralization Effects

“…10,11 Recent examples are selections for the binding of demosponge spicule silica, 12 synthetic silica, 13 ZnO, 14 and GdO. 15 Because the selections can be performed under close-to-physiological conditions, the question has arisen as to whether natural and synthetic selection evolves molecules with similar characteristics and whether the biomineralizing functionality might be encoded in homologue structures for materials also found in organisms.…”

Biogenic and Synthetic Peptides with Oppositely Charged Amino Acids as Binding Sites for Mineralization

“…Based on these findings previously identified ZrO 2 -binding peptides [5] and ZnO-binding peptides [19] were analyzed with regard to such amino acid duplets and a minimum of 20% (corresponding to 25% in a 12-mer peptide) of charged amino acid residues in the peptide sequences. These peptides were selected by phage display from single crystalline ZrO 2 and ZnO substrates, respectively and were further applied for biomineralization approaches [4,5].…”