The assembly and structure of self-assembling peptides: molecular to supramolecular

Self-assembling molecules are central to a plethora of processes found in nature, biotechnology and even disease. The importance of the non-covalent interaction of monomers to the formation of fibrillar assemblies is evident in the repeated use of this mechanism throughout nature, from essential cellular processes such as the formation of the cytoskeleton to the production of silk. Further, it has been recognised in the last two decades that a self-assembly mechanism, that is the formation of amyloid, underpins the pathology of protein misfolding diseases; it is therefore essential to dissect these mechanisms. Despite recent technological and model system developments, self-assembling molecules remain challenging to investigate. Using combined structural and biophysical characterisations of penta- and hexa-peptide self-assembling model systems these investigations shed further light on the structure of amyloid-like fibrils. The elucidation of the structures of these fibrillar systems not only has implications for disease but also makes them well placed for consideration for biotechnological applications. In reflecting upon how cross-ß structural architectures can be organised in the fibrillar state, a molecular and supramolecular model of fibrils formed by a fragment of !-synuclein is reported. The fibrils are found to consist of a novel and elaborate cross-ß architecture that leads to a helical supramolecular assembly spanning length scales previously unobserved for such a system. Where self-assembly is a useful route to supramolecular structure formation, the use of low molecular weight gelator (LMWG) peptides to create fibrillar structures with defined material properties is also explored. The complex link between molecular structure, self-assembled architecture, fibril formation, fibril interaction and ultimately bulk material properties is described. It is found that the determinants of self-assembly are distinct from the determinants of gelation and so future LMWG design will have to consider both individually. This work presents methodological advances in the characterisation of self-assembled structures. The investigations presented here have relevance for disease related processes but also to the technological use of these systems as materials. Finally, this work emphasises the beauty of the extravagant, yet elegant connection between molecular interaction and supramolecular selfassembly

Evans Findings Company: Unattended Stamping

In Fall 2010, Capstone Design Team 6, consisting of Drew Davis, Kyle Morris, Paul Schumacher, and Derek Sutcliffe, designed a part sorting device for the Evans Findings Company. The project’s objective was to meet Evans Co.’s need for a device capable of reducing the scrap rate of parts produced during unattended stamping operations. In Spring 2011, Team 6 built, tested, troubleshot, redesigned, and rebuilt the device to meet the design specifications and Evans Co.’s expectations. The overnight, unattended stamping operations at Evans Co. are currently susceptible to loss; as all finished parts are ejected from the stamping press into one large forty-gallon bin, defective parts can easily contaminate an entire batch. In manufacturing, a lot sorting device is a common countermeasure against batch contamination. The design team generated over 120 concepts before choosing one such device, which has gained approval from Evans Co. The team’s financial analysis shows the payback period will likely meet Evans Co.’s requirements. The final concept consists of six buckets, each on a rolling carriage, constrained by an oval aluminum track. The carriages are pushed around the track by a chain attached to sprockets driven by a stepper motor, which is commanded by an Arduino microcontroller. It should ensure reliable capture of finished parts from the stamping press, sorted into separate buckets by their ejection time, thus providing protection from contamination. The device itself (named the USAD, or Unattended Stamping Assistance Device) was completed on time with a $4,000 budget. Simulation and financial analysis both indicate that the device will pay for itself within one year and save Evans Co. over$7,000 annually by reducing scrap

Allosteric activation of the nitric oxide receptor soluble guanylate cyclase mapped by cryo-electron microscopy.

Soluble guanylate cyclase (sGC) is the primary receptor for nitric oxide (NO) in mammalian nitric oxide signaling. We determined structures of full-length Manduca sexta sGC in both inactive and active states using cryo-electron microscopy. NO and the sGC-specific stimulator YC-1 induce a 71° rotation of the heme-binding β H-NOX and PAS domains. Repositioning of the β H-NOX domain leads to a straightening of the coiled-coil domains, which, in turn, use the motion to move the catalytic domains into an active conformation. YC-1 binds directly between the β H-NOX domain and the two CC domains. The structural elongation of the particle observed in cryo-EM was corroborated in solution using small angle X-ray scattering (SAXS). These structures delineate the endpoints of the allosteric transition responsible for the major cyclic GMP-dependent physiological effects of NO

Combining Targeted DNA Repair Inhibition and Immune-Oncology Approaches for Enhanced Tumor Control

Targeted therapy and immunotherapy have revolutionized cancer treatment. However, the ability of cancer to evade the immune system remains a major barrier for effective treatment. Related to this, several targeted DNA-damage response inhibitors (DDRis) are being tested in the clinic and have been shown to potentiate anti-tumor immune responses. Seminal studies have shown that these agents are highly effective in a pan-cancer class of tumors with genetic defects in key DNA repair genes such as BRCA1/2, BRCA-related genes, ataxia telangiectasia mutated (ATM), and others. Here, we review the molecular consequences of targeted DDR inhibition, from tumor cell death to increased engagement of the anti-tumor immune response. Additionally, we discuss mechanistic and clinical rationale for pairing targeted DDRis with immunotherapy for enhanced tumor control. We also review biomarkers for patient selection and promising new immunotherapy approaches poised to form the foundation of next-generation DDRi and immunotherapy combinations

The diversity and utility of amyloid fibrils formed by short amyloidogenic peptides

Amyloidogenic peptides are well known for their involvement in diseases such as type 2 diabetes and Alzheimer's disease. However, more recently, amyloid fibrils have been shown to provide scaffolding and protection as functional materials in a range of organisms from bacteria to humans. These roles highlight the incredible tensile strength of the cross-β amyloid architecture. Many amino acid sequences are able to self-assemble to form amyloid with a cross-β core. Here we describe our recent advances in understanding how sequence contributes to amyloidogenicity and structure. For example, we describe penta- and hexapeptides that assemble to form different morphologies; a 12mer peptide that forms fibrous crystals; and an eight-residue peptide originating from α-synuclein that has the ability to form nanotubes. This work provides a wide range of peptides that may be exploited as fibrous bionanomaterials. These fibrils provide a scaffold upon which functional groups may be added, or templated assembly may be performed

The Effects of Dried Distillers Grains on Heifers Consuming Low or High Quality Forage

Two forage sources, high and low quality, were used to evaluate effects of five levels of dried distillers grains on forage intake. Ninety heifer calves were fed high or low quality forage, supplemented with 0, 1.5, 3, 4.5, or 6 lb DM dried distillers grains. Forage intakes linearly decreased as dried distillers grains increased. Average daily gain increased linearly with increased dried distillers grains indicating that dried distillers grains can be a protein and energy supplement source and a substitute for forage. Dried distillers grains are an economical supplement to cattle on either high or low quality forage diets