Life Sciences Commons^™

Structural And Functional Characterization Of The Endosome-Associated Deubiquitinating Enzyme Amsh, Christopher Williamson Davies

Open Access Dissertations

The endosomal sorting complexes required for transport (ESCRT) machinery is a ubiquitin-dependent molecular mechanism made of up of four individual complexes: ESCRT-0, -I, -II, III, that is necessary for regulating the degradation of cell surface receptors directed towards the lysosome. Not only are the ESCRTs implicated in endosomal sorting and trafficking of proteins, its members also have roles in other important biological processes such as: cytokinesis, HIV budding, transcriptional regulation, and autophagy. As a function of its involvement in several processes throughout the cell, the ESCRT machinery is implicated in a wide variety of diseases including cancer, neurological disease, bacterial …

Effects Of Dna Methylation Pattern On The Chromatin Structure, Isabel Cristina Jimenez Useche

Open Access Dissertations

DNA methylation plays an essential role in various biological processes such as stem cell differentiation, imprinting, X-chromosome inactivation, etc. Increased DNA methylation levels have been associated with chromatin compaction leading to gene silencing. For example, abnormal DNA methylation is associated with silencing of tumor suppressor genes and is observed in the onset of tumorigenesis. There is evidence suggesting that not all methylation events are relevant in chromatin compaction and the initiation of cancer. It seems that methylation at certain locations of the DNA might be key to start chromatin compaction and gene silencing, but the location of this methylation sites …

The Termite Digestome: Understanding The Digestive Physiology Involved In Lignocellulosic Biomass Degradation, Zachary John Karl

Open Access Dissertations

The purpose of this research was to advance the understanding of lower termite digestive physiology and discover potential biocatalysts that can aid in the degradation of lignocellulosic biomass. Various protein characterization and gene expression methods were used throughout this research in order to accomplish these objectives. The results of this dissertation indicate that: 1) termites and their symbionts act in a synergistic manner to degrade biomass in vitro, 2) the host fraction of the gut (i.e., foregut and midgut) is the likely site of glucose absorption, 3) the termite and its symbionts contribute specific enzymes to the digestive process, 4) …

Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla

Open Access Dissertations

To better understand a class of transporters known as Calcium/Cation Antiporters (CaCAs), the bacterial calcium/proton antiporter CAXCK31 was purified and characterized. New methods were developed for its heterologous overexpression and purification. These methods help to define stress responses to toxic membrane overproduction in E. coli and may be broadly applicable to studies of membrane proteins. The results from a variety of biochemical and biophysical experiments demonstrated that CAXCK31 exists as a dimer in the membrane and can be purified in the dimeric state. The methods used include chemical cross-linking, FRET, and SEC-MALS. In addition, various transport properties of CAXCK31, including …

Structural Studies On The Rubella Virus Capsid Protein And Its Organization In The Virion, Vidya Mangala Prasad

Open Access Dissertations

Rubella virus is a leading cause of birth defects due to infectious agents. When contracted during pregnancy, rubella infection leads to severe damage in fetuses. Despite its medical importance, very little is known about the structure of the pleomorphic rubella virus as compared to its alphavirus relatives. The rubella capsid protein is a critical structural component of virions as well as a key factor in virus-host interactions. Three crystal structures of the structural domain of the rubella capsid protein have been described here. The polypeptide fold of the capsid protomer has not been observed previously. The capsid protein structure, along …

Development Of Tyrosine Kinase Peptide Biosensors And Methods For Detection, Andrew Michael Lipchik

Open Access Dissertations

New methods to monitor tyrosine kinase activity are critical for studying kinases in cell biology, drug discovery and the clinic. Peptide-based biosensors for detection of kinase activity utilitize a kinase specific artificial peptide substrate, which can report intercellular kinase activity through the incorporation of phosphate.

An artificial Syk substrate peptide was developed and incorporated with other functional modules to produce a Syk biosensor. These modules included a biotin-tag for affinity capture, a photo-cleavable amino acid to allow release of the substrate from the delivery module and the cell penetrating peptides TAT. A live cell kinase assay utilizing this biosensor was …

Interaction Between Centromeric Histone H3 Variant And Shugoshin, Visarut Buranasudja

Open Access Theses

Precise and faithful segregation of chromosome segregation during mitosis depends on the ability of the cell to regulate chromosome bi-orientation on the mitotic spindle. Shugoshin (Sgo1), the protector of meiotic centromeric cohesin, is required for proper establishment of chromosome bi-orientation. Sgo1 plays a crucial role as part of a mitotic tension sensor between sister chromatids. Recently, Sgo1 has been reported to interact with histone H3 at the pericentromere region, as an important factor for tension sensing and chromosome segregation. However, the role of Sgo1 in tension sensing at centromere is still elusive. The centromere is the region of attachment of …