| dc.contributor.advisor | Steinem, Claudia Prof. Dr. | |
| dc.contributor.author | Toy, Silan | |
| dc.date.accessioned | 2025-06-12T17:31:44Z | |
| dc.date.issued | 2025-06-12 | |
| dc.identifier.uri | http://resolver.sub.uni-goettingen.de/purl?ediss-11858/16051 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-11308 | |
| dc.format.extent | 185 | de |
| dc.language.iso | eng | de |
| dc.subject.ddc | 540 | de |
| dc.title | Synthesis and Adhesion Properties of E-Cadherin Mimetic Peptides | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Steinem, Claudia Prof. Dr. | |
| dc.date.examination | 2025-02-24 | de |
| dc.description.abstracteng | Cell adhesion molecules (CAMs) are essential for various biological processes, including tissue homeostasis and wound healing. One such molecule, the calcium-dependent protein E-cadherin, is primarily expressed at adherens junctions which connect neighboring epithelial cells. The interaction between E-cadherin molecules occurs at the N-terminal region of the monomer, where the amino acid sequence histidine-alanine-valine (HAV) in the first extracellular (EC1) domain plays a key role in mediating these interactions.
To understand and mimic these E-cadherin-mediated cell-cell interactions, peptides containing the HAV-unit were synthesized using solid-phase peptide synthesis (SPPS). These HAV-peptides were then incorporated into solid-supported membranes through two distinct chemical strategies. One method involved complexing 1,2-dioleoyl-sn-glycero-3-[(N-(5-amino-1-carboxypentyl)iminodiacetic acid)succinyl] (nickel salt) (DOGS-NTA (Ni)) lipid with a polyhistidine-tagged HAV-peptide, while the other utilized in situ Michael addition to attach a terminal Cys-HAV-peptide to a maleimide lipid. Various lengths of HAV-peptides were synthesized to investigate their impact on adhesion properties. Binding of the HAV-peptides to the membrane was verified using Reflectometric Interference Spectroscopy (RIfS) and Attenuated Total Reflectance Infrared (ATR-IR) spectroscopy, which confirmed the successful HAV-peptide attachment to the membrane.
The molecular interactions between HAV-peptides and E-cadherin were investigated using Quartz Crystal Microbalance (QCM). HAV-peptides were immobilized on gold surfaces via Au-thiol coupling, and their binding to Fc-IgG-E-cadherin was studied. This allowed for a comparison of the frequency shifts induced by Fc-IgG-E-cadherin and the Fc-IgG fragment as control, enabling the calculation of the contribution from specific interactions.
Additionally, holographic Video Particle Tracking (hVPT) was employed to investi-gate the behavior of HAV-functionalized beads on cell surfaces. The trajectories of the beads were analyzed, revealing that the beads exhibited strongly confined motion in the presence of HAV-peptides. This confined movement of the beads indicated a specific interaction between the HAV-peptides and E-cadherin on the cell surface, supporting the hypothesis that HAV-peptides interact with E-cadherin.
To further validate the specificity of these interactions, Atomic Force Microscopy (AFM)-based colloidal probe technique (CPT) was used. From force-distance curves, the work of adhesion as well as the maximum adhesion forces could be quantified. The AFM measurements showed that the HAV-peptides significantly increased both the work of adhesion, and the maximum adhesion force compared to the absence of HAV-peptides, indicating that the presence of HAV-peptides promotes stronger adhesive interactions. Due to the complexity of the cell surface, experiments were conducted using polydimethylsiloxane (PDMS) coated with Fc-IgG-E-cadherin and micropatterned Fc-IgG-E-cadherin substrates. The experiments showed a similar trend, with both maximum adhesion force and work of adhesion showing increased values in the presence of HAV-peptides. Additionally, the known lengths of the Fc-IgG-E-cadherin molecules (24 nm for the dimeric form and 37 nm for the stretched form) were used to assign peak-to-peak distances in the force curves to the E-cadherin molecules. This study confirms that HAV-peptides enhance specific E-cadherin-mediated cell adhesion, thereby supporting their role in tissue interactions. | de |
| dc.contributor.coReferee | Thomas, Franziska Jun.-Prof. Dr. | |
| dc.subject.eng | E-Cadherin | de |
| dc.subject.eng | Solid-Phase Peptide Synthesis | de |
| dc.subject.eng | Cell junctions | de |
| dc.subject.eng | Artificial cell tissue | de |
| dc.subject.eng | E-Cadherin Mimetic Peptides | de |
| dc.subject.eng | Colloidal probe technique AFM | de |
| dc.subject.eng | Membranes | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-ediss-16051-1 | |
| dc.date.embargoed | 2026-02-23 | |
| dc.affiliation.institute | Fakultät für Chemie | de |
| dc.subject.gokfull | Chemie (PPN62138352X) | de |
| dc.description.embargoed | 2026-02-23 | de |
| dc.identifier.ppn | 1928230180 | |
| dc.notes.confirmationsent | Confirmation sent 2025-06-12T19:45:01 | de |