Softening of POPC membranes by magainin

International audienc

Peptide-oligonucleotide conjugates as nanoscale building blocks for assembly of an artificial three-helix protein mimic

Peptide-based structures can be designed to yield artificial proteins with specific folding patterns and functions. Template-based assembly of peptide units is one design option, but the use of two orthogonal self-assembly principles, oligonucleotide triple helix and a coiled coil protein domain formation have never been realized for de novo protein design. Here, we show the applicability of peptide–oligonucleotide conjugates for self-assembly of higher-ordered protein-like structures. The resulting nano-assemblies were characterized by ultraviolet-melting, gel electrophoresis, circular dichroism (CD) spectroscopy, small-angle X-ray scattering and transmission electron microscopy. These studies revealed the formation of the desired triple helix and coiled coil domains at low concentrations, while a dimer of trimers was dominating at high concentration. CD spectroscopy showed an extraordinarily high degree of α-helicity for the peptide moieties in the assemblies. The results validate the use of orthogonal self-assembly principles as a paradigm for de novo protein design

A brain-targeting lipidated peptide for neutralizing RNA-mediated toxicity in Polyglutamine Diseases

Abstract Polyglutamine (PolyQ) diseases are progressive neurodegenerative disorders caused by both protein- and RNA-mediated toxicities. We previously showed that a peptidyl inhibitor, P3, which binds directly to expanded CAG RNA can inhibit RNA-induced nucleolar stress and suppress RNA-induced neurotoxicity. Here we report a N-acetylated and C-amidated derivative of P3, P3V8, that showed a more than 20-fold increase in its affinity for expanded CAG RNA. The P3V8 peptide also more potently alleviated expanded RNA-induced cytotoxicity in vitro, and suppressed polyQ neurodegeneration in Drosophila with no observed toxic effects. Further N-palmitoylation of P3V8 (L1P3V8) not only significantly improved its cellular uptake and stability, but also facilitated its systemic exposure and brain uptake in rats via intranasal administration. Our findings demonstrate that concomitant N-acetylation, C-amidation and palmitoylation of P3 significantly improve both its bioactivity and pharmacological profile. L1P3V8 possesses drug/lead-like properties that can be further developed into a lead inhibitor for the treatment of polyQ diseases

CATANIONIC SURFACTANT VESICLES: TECHNOLOGY FOR VACCINE DEVELOPMENT AND TARGETED DRUG DELIVERY APPLICATIONS

Catanionic surfactant vesicles have gained attention due to their structural similarities to liposomes and their robust properties in biological media. Catanionic vesicles are formed from oppositely charged surfactants and can be exploited for applications in vaccine production and drug delivery. The focus of my research has been on the preparation, characterization, and application of functionalized catanionic surfactant vesicles. Chapter 2 describes the preparation and characterization of catanionic vesicles containing sodium dodecylbenzenesulfonate (SDBS) and cetyltrimethylammonium tosylate (CTAT). Vesicle solutions were determined to be stable for greater than 6 months, formed vesicles with two populations of 80 and 160 nm, and had a membrane surface charge similar to human cells, -56 mV. Furthermore, vesicles were stable between a pH of 2 and 12, in saline solutions up to 0.6 M NaCl, and after autoclaving. Next, I report the loading of various molecules into the vesicle leaflet and the characterization of the resulting functionalized systems. Hydrophobic molecules were readily incorporated into the hydrophobic region of the leaflet. Lipid conjugates of hydrophilic molecules were anchored in the vesicle bilayer. Chapters 3 and 4 report the loading of biological materials (i.e. liposaccharides and proteins) into catanionic vesicles for the development of bacterial vaccines. Initial studies, discussed in Chapter 3, pertain to the loading of the pure components lipooligosaccharide (LOS) and C12 -Pan DR helper T cell epitope (PADRE) conjugate into catanionic vesicles. A single dose of these vesicles generated a large IgG antibody titer in mice. Next, in Chapter 4, we focus on the extraction of cellular membrane components from cells for their direct incorporation into catanionic vesicles. Vesicles were prepared by adding surfactants in the presence of Neisseria gonorrhoeae cells. Vesicle extracts contained pathogen-derived LOS F62ΔlgtD and a subset of proteins from the outer membrane of the bacterium, including porin and OPA. Lastly, Chapter 5 describes catanionic vesicles in drug delivery. Vesicles were loaded with 88 μg/mL of doxorubicin and shown to retain the drug over 15 days. Doxorubicin loaded into catanionic vesicles were shown to be less toxic as compared to the free drug, IC 50 = 51 μg/mL and 0.16 μg/mL, respectively

Selective N-terminal acylation of peptides and proteins with a Gly-His tag sequence

His-tagged proteins can undergo N-terminal acylation as an undesired side-reaction. Here, the authors utilize this to develop a method for highly selective acylation and further modification of peptides and proteins using an optimized His sequence and 4-methoxyphenyl esters as acyl donors

DANSKE BYBOERS MØDE MED LEJESOLDATER UNDER SYVÅRSKRIGEN

ABSTRACTEncounters between Danish townspeople and mercenaries during the SevenYears’ WarThis article explores the relations between townspeople and mercenaries in the Danish realm during the so-called Seven Years’ War of 1563-1570 between the Danish and Swedish kings. Drawing on a range of sources including royal instructions, petitions from town dwellers to the king, municipal records, plays and contemporary woodcuts, the article examines how the townspeople perceived the Scottish and German mercenaries with whom they come into close contact when soldiers were billeted in the towns before and after deployment. The article presents a number of examples of very different forms of interaction and encounters between mercenaries and town dwellers, ranging from riots, robberies, ructions and rape to marriage and enrolment in municipal guilds. These are used to highlight how the townspeople’s perceptions of the mercenaries varied depending on a variety of factors, including the individual town dweller’s previous personal experiences, age, values and norms as well as social and economic status