We have analyzed the adsorption of protein to the surfaces of silica nanoparticles with diameters of 6, 9, and 15 nm. The effects upon adsorption on variants of human carbonic anhydrase with differing conformational stabilities have been monitored using methods that give complementary information, i.e., circular dichroism (CD), nuclear magnetic resonance (NMR), analytical ultracentrifugation (AUC)

It is well-known that adsorption of proteins on interfaces often induces substantial alterations of the protein structure. However, very little is known about whether these conformational changes have any consequence for the protein conformation after desorption from the interface. To investigate this matter, we have selected a protein−particle system in which the enzyme human carbonic anhydrase I

Cholinesterase-like adhesion molecules (CLAMs) are a family of neuronal cell adhesion molecules with important roles in synaptogenesis, and in maintaining structural and functional integrity of the nervous system. Our earlier study on the cytoplasmic domain of one of these CLAMs, the Drosophila protein, gliotactin, showed that it is intrinsically unstructured in vitro. Bioinformatic analysis sugge

To characterize the sites on the protein surface that are involved in the adsorption to silica nanoparticles and the subsequent rearrangements of the protein/nanoparticle interaction, a novel approach has been used. After incubation of protein with silica nanoparticles for 2 or 16 h, the protein was cleaved with trypsin and the peptide fragments were analyzed with mass spectrometry. The nanopartic

More than 100 distinct mutations in the gene (SOD1) for human copper-zinc superoxide dismutase (CuZnSOD) have been associated with familial amyotrophic lateral sclerosis (fALS). Studies of these mutant proteins, which often have been performed under far from physiological conditions, have indicated effects on protein stabilities, catalytic activity, and metal binding affinities but with no common

We have shown that it is possible to design a peptide that has a very low helical content when free in solution but that adopts a well-defined helix when interacting with silica nanoparticles. From a systematic variation of the amino acid composition and distribution in designed peptides, it has been shown that the ability to form helical structure upon binding to the silica surface is dominated b

Homeodomains are one of the key families of eukaryotic DNA-binding motifs and provide an important model system for DNA recognition. We have determined a high-quality nuclear magnetic resonance (NMR) structure of the DNA-binding homeodomain of the insulin gene enhancer protein Isl-1 (Isl-1-HD). It forms the first solution structure of a homeodomain from the LIM family. It contains a well-defined i

Without evidence for an organic framework, biological and biochemical processes observed during amelogenesis provided limited information on how extracellular matrix proteins control the development of the complex fibrous architecture of human enamel. Over a decade ago, amelogenin nanoribbons were first observed from recombinant proteins during in vitro mineralization experiments in our laboratory

We show that it is possible to induce a defined secondary structure in de novo designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solutio

We have analysed hydrogen exchange at amide groups to characterise the energy landscape of the 72 amino acid residue protein MerP. From the guanidine hydrochloride (GuHCl) dependence of exchange in the pre-transitional region we have determined free energy values of exchange (ΔGHX) and corresponding m-values for individual amide protons. Detailed analysis of the exchange patterns indicates that fo

The role of proteins as the mediators of the interaction between engineered materials (biomaterials) and living systems has long been appreciated, but the subtleties and complexities introduced by changing surface curvature are only beginning to be understood. Thus, in implant devices, where the biomaterial is presented as a flat surface, a very limited range of proteins bind to the material, thes

PurposeWear of ceramic orthopedic devices generates nanoparticles in vivo that may present a different biological character from the monolithic ceramic from which they are formed. The current work investigated protein adsorption from human plasma on alumina nanoparticles and monolithic samples representative of both wear particles and the ceramic components as implanted.Materials and MethodsA phys

Nanoparticles in a biological fluid (plasma, or otherwise) associate with a range of biopolymers, especially proteins, organized into the “protein corona” that is associated with the nanoparticle and continuously exchanging with the proteins in the environment. Methodologies to determine the corona and to understand its dependence on nanomaterial properties are likely to become important in bionan

Nanoparticles can be used to purify proteins from plasma. We report here the purification of apolipoprotein A-I (apoA-I) with high specificity from human plasma using copolymeric nanoparticles. We present an optimized protocol using 50:50 NiPAM:BAM copolymer nanoparticles with thermo-responsive properties as an affinity resin. Repeated pelleting and washing of nanoparticle-captured apoA-I is achie

The global increase in species richness toward the tropics across continents and taxonomic groups, referred to as the latitudinal diversity gradient, stimulated the formulation of many hypotheses to explain the underlying mechanisms of this pattern. We evaluate several of these hypotheses to explain spatial diversity patterns in a butterfly family, the Nymphalidae, by assessing the contributions o

Urbanization is gaining force globally, which challenges biodiversity, and it has recently also emerged as an agent of evolutionary change. Seasonal phenology and life cycle regulation are essential processes that urbanization is likely to alter through both the urban heat island effect (UHI) and artificial light at night (ALAN). However, how UHI and ALAN affect the evolution of seasonal adaptatio

A numerical scheme is presented for the solution of Fredholm second-kind boundary integral equations with right-hand sides that are singular at a finite set of boundary points. The boundaries themselves may be non-smooth. The scheme, which builds on recursively compressed inverse preconditioning (RCIP), is universal as it is independent of the nature of the singularities. Strong right-hand-side si

The emergence of COVID-19 has changed the world as we know it, arguably none more so than for older people. In Sweden, the majority of COVID-19-related fatalities have been among people aged ⩾70 years, many of whom were receiving health and social care services. The pandemic has illuminated aspects within the care continuum requiring evaluative research, such as decision-making processes, the stru