LcrH, a Class II Chaperone from the Type Three Secretion System, Has a Highly Flexible Native Structure

Soft Matter Chemistr

Controlling amphipathic peptide adsorption by smart switchable germanium interfaces

The in situ control of reversible protein adsorption to a surface is a critical step towards biofouling prevention and finds utilisation in bioanalytical applications. In this work, adsorption of peptides is controlled by employing the electrode potential induced, reversible change of germanium (100) surface termination between a hydrophobic, hydrogen terminated and a hydrophilic, hydroxyl terminated surface. This simple but effective 'smart' interface is used to direct adsorption of two peptides models, representing the naturally highly abundant structural motifs of amphipathic helices and coiled-coils. Their structural similarity coincides with their opposite overall charge and hence allows the examination of the influence of charge and hydrophobicity on adsorption. Polarized attenuated total reflection infrared (ATR-IR) spectroscopy at controlled electrode potential has been used to follow the adsorption process at physiological pH in deuterated buffer. The delicate balance of hydrophobic and electrostatic peptide/surface interactions leads to two different processes upon switching that are both observed in situ: reversible adsorption and reversible reorientation. Negatively charged peptide adsorption can be fully controlled by switching to the hydrophobic interface, while the same switch causes the positively charged, helical peptide to tilt down. This principle can be used for 'smart' adsorption control of a wider variety of proteins and peptides and hence find application, as e.g. a bioanalytical tool or functional biosensor.Supramolecular & Biomaterials Chemistr

Self-assembly of thiolated versus non-thiolated peptide amphiphiles

Drug Delivery Technolog

Magnetic-activated cell sorting using coiled-coil peptides: an alternative strategy for isolating cells with high efficiency and specificity

NWOSupramolecular & Biomaterials Chemistr

Gold nanoparticles decorated with ovalbumin-derived epitopes: effect of shape and size on T-cell immune responses

Gold nanoparticles (GNPs) can be manufactured in various shapes, and their size is programmable, which permits the study of the effects imposed by these parameters on biological processes. However, there is currently no clear evidence that a certain shape or size is beneficial. To address this issue, we have utilised GNPs and gold nanorods (GNRs) functionalised with model epitopes derived from chicken ovalbumin (OVA(257-264) and OVA(323-339)). By using two distinct epitopes, it was possible to draw conclusions regarding the impact of nanoparticle shape and size on different aspects of the immune response. Our findings indicate that the peptide amphiphile-coated GNPs and GNRs are a safe and versatile epitope-presenting system. Smaller GNPs (similar to 15 nm in diameter) induce significantly less intense T-cell responses. Furthermore, effective antigen presentation via MHC-I was observed for larger spherical particles (similar to 40 nm in diameter), and to a lesser extent for rod-like particles (40 by 15 nm). At the same time, antigen presentation via MHC-II strongly correlated with the cellular uptake, with smaller GNPs being the least efficient. We believe these findings will have implications for vaccine development, and lead to a better understanding of cellular uptake and antigen egress from lysosomes into the cytosol.Microbial BiotechnologyBiopharmaceuticsEnvironmental BiologySupramolecular & Biomaterials Chemistr

Cystic Fibrosis Foundation and European Cystic Fibrosis Society Survey of cystic fibrosis mental health care delivery

Background: Psychological morbidity in individuals with cystic fibrosis (CF) and their caregivers is common. The Cystic Fibrosis Foundation (CFF) and European Cystic Fibrosis Society (ECFS) Guidelines Committee on Mental Health sought the views of CF health care professionals concerning mental health care delivery. Methods: An online survey which focused on the current provision and barriers to mental health care was distributed to CF health care professionals. Results: Of the 1454 respondents, many did not have a colleague trained in mental health issues and 20% had no one on their team whose primary role was focused on assessing or treating these issues. Insufficient resources and a lack of competency were reported in relation to mental health referrals. Seventy-three percent of respondents had no experience with mental health screening. Of those who did, they utilized 48 different, validated scales. Conclusions: These data have informed the decision-making, dissemination and implementation strategies of the Mental Health Guidelines Committee sponsored by the CFF and ECFS

Probing coiled-coil assembly by paramagnetic NMR spectroscopy

Supramolecular & Biomaterials Chemistr

Enhanced liposomal drug delivery via membrane fusion triggered by dimeric coiled‐coil peptides

NWO724.014.001Supramolecular & Biomaterials Chemistr

Distinct roles of SNARE-mimicking lipopeptides during initial steps of membrane fusion

NWOSupramolecular & Biomaterials Chemistr

One Peptide for Them All: Gold Nanoparticles of Different Sizes Are Stabilized by a Common Peptide Amphiphile

The functionalization of gold nanoparticles (GNPs) with peptidic moieties can prevent their aggregation and facilitate their use for applications both in vitro and in vivo. To date, no peptide-based coating has been shown to stabilize GNPs larger than 30 nm in diameter; such particles are of interest for applications including vaccine development, drug delivery, and sensing. Here, GNPs with diameters of 20, 40, and 100 nm are functionalized with peptide amphiphiles. Using a combination of transmission electron microscopy, UV–vis spectroscopy, and dynamic light scattering, we show that GNPs up to 100 nm in size can be stabilized by these molecules. Moreover, we demonstrate that these peptide amphiphiles form curvature-dependent, ordered structures on the surface of the GNPs and that the GNPs remain disperse at high-salt concentrations and in the presence of competing thiol-containing molecules. These results represent the development of a peptide amphiphile-based coating system for GNPs which has the potential to be beneficial for a wide range of biological applications, in addition to image enhancement and catalysis.Supramolecular & Biomaterials Chemistr