Biophysics Commons^™

Nanoscale Morphological Perturbations Of Lipid Membranes Induced By Membrane Active Peptides, Yasith Sandeepa Indigahawela Gamage

USF Tampa Graduate Theses and Dissertations

Membrane-active peptides (MAPs) are a diverse group of biologically relevant molecules that induce nanoscale modulations during their interactions with cell membranes. Understanding the precise mechanism by which these MAPs perturb or modulate the cell membranes is a cornerstone of membrane biophysics, as it facilitates rational design of useful therapeutics. That is, if we have the knowledge to determine what the peptide can do, how selective it is, or how toxic it might be, we can optimize them and design new peptide therapeutics such as for antimicrobial, anticancer, or drug-delivery applications. In general, MAPs can be categorized into two classes based …

The Interactions Of Centromeric Nucleosomes Elucidated By Atomic Force Microscopy, Shaun Filliaux

Theses & Dissertations

Nucleosomes are the fundamental unit of compaction for DNA in the genome. These positively charged proteins have two main types of nucleosomes: canonical (H3 containing) and centromere (CENP-A containing). The compacting of DNA allows for DNA to fit into the nucleus of cells, but creates a barrier for DNA accessibility for operations such as replication or transcription. Centromeric chromatin is a subset of chromatin structure and governs chromosome segregation. Compared to the bulk chromosome, centromeres are composed of H3 and CENP-A nucleosomes in which H3 histones is replaced by its homolog CENP-A histone. This results in nucleosomes with different structures, …

Biomechanical And Biophysical Properties Of Breast Cancer Cells Under Varying Glycemic Regimens, Diganta Dutta, Xavier-Lewis Palmer, Jose Ortega-Rodas, Vasundhara Balraj, Indrani Ghosh Dastider, Surabhi Chandra

Electrical & Computer Engineering Faculty Publications

Diabetes accelerates cancer cell proliferation and metastasis, particularly for cancers of the pancreas, liver, breast, colon, and skin. While pathways linking the 2 disease conditions have been explored extensively, there is a lack of information on whether there could be cytoarchitectural changes induced by glucose which predispose cancer cells to aggressive phenotypes. It was thus hypothesized that exposure to diabetes/high glucose alters the biomechanical and biophysical properties of cancer cells more than the normal cells, which aids in advancing the cancer. For this study, atomic force microscopy indentation was used through microscale probing of multiple human breast cancer cells (MCF-7, …

The Impacts Of Membrane Modulators On Membrane Material Properties At Microscopic And Nanoscopic Levels, Chinta Mani Aryal

USF Tampa Graduate Theses and Dissertations

Peptide-membrane interactions depict the cell’s response to an external molecule. This is a critical event to evaluate the peptide’s function and effect as well as the response of target molecule. The understanding of the mechanism of action of peptide in a molecular level is important, for example, this may be useful in developing the therapeutic strategy. Peptides are the functional macromolecules which are actively researched among bio-related fields. Model membrane systems that mimic the real cell have been useful platform to test the perturbation upon peptide addition. In this thesis, we investigate the membrane modulation behavior of three peptides (modulators) …

Modulations Of Lipid Membranes Caused By Antimicrobial Agents And Helix 0 Of Endophilin, Nawal Kishore Khadka

USF Tampa Graduate Theses and Dissertations

Understanding the cellular membrane interaction with membrane active biomolecules and antimicrobial agents provides an insight in their working mechanism. Here, we studied the effect of antimicrobial agents; a recently developed peptidomimetics E107-3 and colistin as well as the N-terminal helix H0, of Endophilin A1 on the lipid bilayer.

It is important to discern the interaction mechanism of antimicrobial peptides with lipid membranes in battling multidrug resistant bacterial pathogens. We study the modification of structural and mechanical properties with a recently reported peptidomimetic on lipid bilayer. The compound referred to as E107-3 is synthesized based on the acylated reduced amide scaffold …

Molecular Mechanism Of Early Amyloid Self-Assembly Revealed By Computational Modeling, Mohtadin Hashemi

Theses & Dissertations

Protein misfolding followed by the formation of aggregates, is an early step in the cascade of conformational changes in a protein that underlie the development of several neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. Efforts aimed at understanding this process have produced little clarity and the mechanism remains elusive.

Here, we demonstrate that the hairpin fold, a structure found in the early folding intermediates of amyloid b, induces morphological and stability changes in the aggregates of Aβ(14-23) peptide. We structurally characterized the interactions of monomer and hairpin using extended molecular dynamics (MD) simulations, which revealed a novel intercalated type complex. …