Search results for "assembly"

Assembly of modular asymmetric organic-inorganic polyoxometalate hybrids into anisotropic nanostructures.

2010

Three organic-inorganic hybrid Mn-Anderson polyoxometalates (POMs), with both symmetrical and asymmetrical appended groups, have been synthesized, identified using electrospray mass spectrometry, and isolated using an approach that allows the three AA, BB, and AB compounds to be structurally characterized. Investigation of the self-assembly of the hybrids on hydrophilic surfaces reveals the formation of nanofibres with characteristics that reflect the nature of the substitution of the POM yielding a route to the programmed assembly of anisotropic hybrid nanostructures.

Positional Isomers of Chromophore–Peptide Conjugates Self-Assemble into Different Morphologies

2018

Ordering π-systems into defined supramolecular structures is important for the development of organic functional materials. In recent years, peptides with defined secondary structures and/or self-assembly properties were introduced as powerful tools to order peptide-chromophore conjugates into different morphologies. This work explores whether or not the directionality of peptides can be used to control the self-assembly. The position of the π-system in conjugates between oligoprolines and perylene monoimide (PMI) chromophores was varied by attaching the PMI moiety to the second-to-last residue from the C- and N-termini, respectively. Microscopic and diffraction analysis revealed that the p…

Sizzled Is Unique among Secreted Frizzled-related Proteins for Its Ability to Specifically Inhibit Bone Morphogenetic Protein-1 (BMP-1)/Tolloid-like …

2012

BMP-1/tolloid-like proteinases (BTPs) are major enzymes involved in extracellular matrix assembly and activation of bioactive molecules, both growth factors and anti-angiogenic molecules. Although the control of BTP activity by several enhancing molecules is well established, the possibility that regulation also occurs through endogenous inhibitors is still debated. Secreted frizzled-related proteins (sFRPs) have been studied as possible candidates, with highly contradictory results, after the demonstration that sizzled, a sFRP found in Xenopus and zebrafish, was a potent inhibitor of Xenopus and zebrafish tolloid-like proteases. In this study, we demonstrate that mammalian sFRP-1, -2, and …

Bacteriophage P23-77 capsid protein structures reveal the archetype of an ancient branch from a major virus lineage.

2013

Summary It has proved difficult to classify viruses unless they are closely related since their rapid evolution hinders detection of remote evolutionary relationships in their genetic sequences. However, structure varies more slowly than sequence, allowing deeper evolutionary relationships to be detected. Bacteriophage P23-77 is an example of a newly identified viral lineage, with members inhabiting extreme environments. We have solved multiple crystal structures of the major capsid proteins VP16 and VP17 of bacteriophage P23-77. They fit the 14 Å resolution cryo-electron microscopy reconstruction of the entire virus exquisitely well, allowing us to propose a model for both the capsid archi…

Cyclodextrin and Adamantane Host-Guest Interactions of Modified Hyperbranched Poly(ethylene imine) as Mimetics for Biological Membranes

2011

Identification of SNARE complex modulators that inhibit exocytosis from an alpha-helix-constrained combinatorial library.

2003

Synthetic peptides patterned after the proteins involved in vesicle fusion [the so-called SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins] are potent inhibitors of SNARE complex assembly and neuronal exocytosis. It is noteworthy that the identification of peptide sequences not related to the SNARE proteins has not been accomplished yet; this is due, in part, to the structural constraints and the specificity of the protein interactions that govern the formation of the SNARE complex. Here we have addressed this question and used a combinatorial approach to identify peptides that modulate the assembly of the SNARE core complex and inhibit neuronal…

Dynamical Properties of Self-Assembled Surfactant-Based Mixtures: Triggering of One-Dimensional Anomalous Diffusion in Bis(2-ethylhexyl)phosphoric Ac…

2013

The dynamic features of bis(2-ethylhexyl)phosphoric acid (HDEHP)/n-octylamine (NOA) mixtures have been investigated as a function of the NOA mole fraction and temperature by (1)H NMR spectroscopy and rheometry. All data consistently suggest a composition-induced glass-forming behavior. The microscopic factors responsible for this behavior have been highlighted and have been explained in terms of driving forces given by HDEHP-to-NOA proton transfer, the tendency of the resulting species to establish H bonds and to spatially segregate the alkyl chains. The study sheds light on the molecular mechanism responsible for the peculiar behavior of transport properties in such systems and furnishes b…

The Minor Capsid Protein VP11 of Thermophilic Bacteriophage P23-77 Facilitates Virus Assembly by Using Lipid-Protein Interactions

2015

ABSTRACT Thermus thermophilus bacteriophage P23-77 is the type member of a new virus family of icosahedral, tailless, inner-membrane-containing double-stranded DNA (dsDNA) viruses infecting thermophilic bacteria and halophilic archaea. The viruses have a unique capsid architecture consisting of two major capsid proteins assembled in various building blocks. We analyzed the function of the minor capsid protein VP11, which is the third known capsid component in bacteriophage P23-77. Our findings show that VP11 is a dynamically elongated dimer with a predominantly α-helical secondary structure and high thermal stability. The high proportion of basic amino acids in the protein enables electrost…

The Modular X- and Gamma-Ray Sensor (MXGS)of the ASIM Payload on the International Space Station

2019

The Modular X- and Gamma-ray Sensor (MXGS) is an imaging and spectral X- and Gamma-ray instrument mounted on the starboard side of the Columbus module on the International Space Station. Together with the Modular Multi-Spectral Imaging Assembly (MMIA) (Chanrion et al. this issue) MXGS constitutes the instruments of the Atmosphere-Space Interactions Monitor (ASIM) (Neubert et al. this issue). The main objectives of MXGS are to image and measure the spectrum of X- and γ-rays from lightning discharges, known as Terrestrial Gamma-ray Flashes (TGFs), and for MMIA to image and perform high speed photometry of Transient Luminous Events (TLEs) and lightning discharges. With these two instruments sp…

Scaffold and scaffold-free self-assembled systems in regenerative medicine.

2016

Self-assembly in tissue engineering refers to the spontaneous chemical or biological association of components to form a distinct functional construct, reminiscent of native tissue. Such self-assembled systems have been widely used to develop platforms for the delivery of therapeutic and/or bioactive molecules and various cell populations. Tissue morphology and functional characteristics have been recapitulated in several self-assembled constructs, designed to incorporate stimuli responsiveness and controlled architecture through spatial confinement or field manipulation. In parallel, owing to substantial functional properties, scaffold-free cell-assembled devices have aided in the developm…