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Full-Text Articles in Life Sciences

Sequence Determinants Of The Individual And Collective Behaviour Of Intrinsically Disordered Proteins, Alexander S. Holehouse Aug 2017

Sequence Determinants Of The Individual And Collective Behaviour Of Intrinsically Disordered Proteins, Alexander S. Holehouse

Arts & Sciences Electronic Theses and Dissertations

Intrinsically disordered proteins and protein regions (IDPs) represent around thirty percent of the eukaryotic proteome. IDPs do not fold into a set three dimensional structure, but instead exist in an ensemble of inter-converting states. Despite being disordered, IDPs are decidedly not random; well-defined - albeit transient - local and long-range interactions give rise to an ensemble with distinct statistical biases over many length-scales. Among a variety of cellular roles, IDPs drive and modulate the formation of phase separated intracellular condensates, non-stoichiometric assemblies of protein and nucleic acid that serve many functions. In this work, we have explored how the amino …


Determining The Molecular Mechanisms Of Huntington’S Disease Through Multi-Scale Modeling, Kiersten Ruff Aug 2017

Determining The Molecular Mechanisms Of Huntington’S Disease Through Multi-Scale Modeling, Kiersten Ruff

Arts & Sciences Electronic Theses and Dissertations

Huntington’s disease (HD) is associated with a mutational CAG repeat expansion within exon 1 of the huntingtin (Htt) gene. Post-transcriptional processing leads to the generation of N-terminal Htt protein fragments (Htt-NTFs), including those that encompass exon 1 (Httex1). Within Httex1, the CAG-repeat encoded polyglutamine (polyQ) tract is flanked N-terminally by a 17-residue amphipathic stretch (N17) and C-terminally by a 50-residue proline rich (PR) domain. Htt-NTFs, including Httex1, are among the smallest fragments that recapitulate HD pathology in mouse models. However, the direct link between Htt-NTFs with polyQ expansions and neurodegeneration that leads to HD remains unresolved. Despite being a monogenic …


Structural, Biophysical, And Functional Studies Of Trem2 In Neurodegenerative Disease, Daniel L. Kober May 2017

Structural, Biophysical, And Functional Studies Of Trem2 In Neurodegenerative Disease, Daniel L. Kober

Arts & Sciences Electronic Theses and Dissertations

Alzheimer's disease (AD) and other neurodegenerative diseases present a large and growing challenge to global health. The immune system, particularly the innate immune system, is increasingly recognized as having a major role in these pathologies. The innate immune system is responsible to contain disease and promote healing. However, immune misregulation exacerbates disease. The innate immunomodulatory receptor Triggering receptor expressed on myeloid cells-2 (TREM2) is expressed on myeloid cells such as dendritic cells, macrophages, and in the brain, on microglia. TREM2 is a single-pass transmembrane receptor with an extracellular Ig domain that mediates ligand binding. This protein regulates inflammation in vitro …


Disordered Proteins: Connecting Sequences To Emergent Properties, Tyler Scott Harmon May 2017

Disordered Proteins: Connecting Sequences To Emergent Properties, Tyler Scott Harmon

Arts & Sciences Electronic Theses and Dissertations

Many IDPs participate in coupled folding and binding reactions and form alpha helical structures in their bound complexes. Alanine, glycine, or proline scanning mutagenesis approaches are often used to dissect the contributions of intrinsic helicities to coupled folding and binding. These experiments can yield confounding results because the mutagenesis strategy changes the amino acid compositions of IDPs. Therefore, an important next step in mutagenesis-based approaches to mechanistic studies of coupled folding and binding is the design of sequences that satisfy three major constraints. These are (i) achieving a target intrinsic alpha helicity profile; (ii) fixing the positions of residues corresponding …


Tissue Damage Quantification In Alzheimer's Disease Brain Via Magnetic Resonance Gradient Echo Plural Contrast Imaging (Gepci), Yue Zhao May 2017

Tissue Damage Quantification In Alzheimer's Disease Brain Via Magnetic Resonance Gradient Echo Plural Contrast Imaging (Gepci), Yue Zhao

Arts & Sciences Electronic Theses and Dissertations

Alzheimer’s disease (AD) affected approximately 48 million people worldwide in 2015. Its devastating consequences have stimulated an intense search for AD prevention and treatment. Clinically, AD is characterized by memory deficits and progressive cognitive impairment, leading to dementia. Over the past two to three decades, researchers have found that amyloidbeta (Aβ) plaques and neurofibrillary tau tangles occur during a long pre-symptomatic period (preclinical stage) before the onset of clinical symptoms. As a result, identification of the preclinical stage is essential for the initiation of prevention trials in asymptomatic individuals. Currently, Positron Emission Tomography (PET) imaging with injected 11C or 18F …