Alteration of Neuropilin‑1 and Heparan Sulfate Interaction Impairs Murine B16 Tumor Growth

Neuropilin-1 acts as a coreceptor with vascular endothelial growth factor receptors to facilitate binding of its ligand, vascular endothelial growth factor. Neuropilin-1 also binds to heparan sulfate, but the functional significance of this interaction has not been established. A combinatorial library screening using heparin oligosaccharides followed by molecular dynamics simulations of a heparin tetradecasaccharide suggested a highly conserved binding site composed of amino acid residues extending across the b1 and b2 domains of murine neuropilin-1. Mutagenesis studies established the importance of arginine513 and lysine514 for binding of heparin to a recombinant form of Nrp1 composed of the a1, a2, b1, and b2 domains. Recombinant Nrp1 protein bearing R513A,K514A mutations showed a significant loss of heparin-binding, heparin-induced dimerization, and heparin-dependent thermal stabilization. Isothermal calorimetry experiments suggested a 1:2 complex of heparin tetradecasaccharide:Nrp1. To study the impact of altered heparin binding in vivo, a mutant allele of Nrp1 bearing the R513A,K514A mutations was created in mice (Nrp1D) and crossbred to Nrp1+/- mice to examine the impact of altered heparan sulfate binding. Analysis of tumor formation showed variable effects on tumor growth in Nrp1D/D mice, resulting in a frank reduction in tumor growth in Nrp1D/- mice. Expression of mutant Nrp1D protein was normal in tissues, suggesting that the reduction in tumor growth was due to the altered binding of heparin/heparan sulfate to neuropilin-1. These findings suggest that the interaction of neuropilin-1 with heparan sulfate modulates its stability and its role in tumor formation and growth

A steric tethering approach enables palladium-catalysed C-H activation of primary amino alcohols.

Aliphatic primary amines are a class of chemical feedstock essential to the synthesis of higher-order nitrogen-containing molecules, commonly found in biologically active compounds and pharmaceutical agents. New methods for the construction of complex amines remain a continuous challenge to synthetic chemists. Here, we outline a general palladium-catalysed strategy for the functionalization of aliphatic C-H bonds within amino alcohols, an important class of small molecule. Central to this strategy is the temporary conversion of catalytically incompatible primary amino alcohols into hindered secondary amines that are capable of undergoing a sterically promoted palladium-catalysed C-H activation. Furthermore, a hydrogen bond between amine and catalyst intensifies interactions around the palladium and orients the aliphatic amine substituents in an ideal geometry for C-H activation. This catalytic method directly transforms simple, easily accessible amines into highly substituted, functionally concentrated and structurally diverse products, and can streamline the synthesis of biologically important amine-containing molecules.We are grateful to the Marie Curie Foundation (D.P. & J.C.), EPSRC (T.W.G.), the ERC (V.D.), and the ERC and EPSRC for Fellowships (M.J.G.). We are grateful to Adam Smalley for DFT calculations and Yohei Shimidzu for assistance with optimization of the C–H acetoxylation reaction. Mass spectrometry data was acquired at the EPSRC UK National Mass Spectrometry Facility at Swansea University. The authors declare no competing financial interests.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nchem.236

Enantioselective, intermolecular benzylic C–H amination catalysed by an engineered iron-haem enzyme

C–H bonds are ubiquitous structural units of organic molecules. Although these bonds are generally considered to be chemically inert, the recent emergence of methods for C–H functionalization promises to transform the way synthetic chemistry is performed. The intermolecular amination of C–H bonds represents a particularly desirable and challenging transformation for which no efficient, highly selective, and renewable catalysts exist. Here we report the directed evolution of an iron-containing enzymatic catalyst—based on a cytochrome P450 monooxygenase—for the highly enantioselective intermolecular amination of benzylic C–H bonds. The biocatalyst is capable of up to 1,300 turnovers, exhibits excellent enantioselectivities, and provides access to valuable benzylic amines. Iron complexes are generally poor catalysts for C–H amination: in this catalyst, the enzyme's protein framework confers activity on an otherwise unreactive iron-haem cofactor

Engineering supported membranes for cell biology

Cell membranes exhibit multiple layers of complexity, ranging from their specific molecular content to their emergent mechanical properties and dynamic spatial organization. Both compositional and geometrical organizations of membrane components are known to play important roles in life processes, including signal transduction. Supported membranes, comprised of a bilayer assembly of phospholipids on the solid substrate, have been productively served as model systems to study wide range problems in cell biology. Because lateral mobility of membrane components is readily preserved, supported lipid membranes with signaling molecules can be utilized to effectively trigger various intercellular reactions. The spatial organization and mechanical deformation of supported membranes can also be manipulated by patterning underlying substrates with modern micro- and nano-fabrication techniques. This article focuses on various applications and methods to spatially patterned biomembranes by means of curvature modulations and spatial reorganizations, and utilizing them to interface with live cells. The integration of biological components into synthetic devices provides a unique approach to investigate molecular mechanisms in cell biology

Possible applications of dietary fibre in functional food production

Dynamizacja przemysłu spożywczego w zakresie projektowania nowej lub wzbogaconej żywności i poszerzania asortymentu produktów na rynku jest elementem rywalizacji zarówno pomiędzy branżami przemysłu spożywczego, jak i poszczególnymi producentami. Producenci dążą do zaoferowania konsu- mentom jak najszerszej gamy produktów korzystnych pod względem wartości odżywczej, właściwości prozdrowotnych i funkcjonalnych, o przedłużonym terminie przydatności do spożycia, a także atrakcyj- nych cenowo. Taka strategia rynkowa pozwala zdobyć przewagę konkurencyjną, jak również promować stosowanie najnowszych rozwiązań technologicznych. Wzrost zainteresowania i świadomości konsumen- tów w zakresie prawidłowego żywienia spowodował rozszerzenie wymagań dotyczących jakości, w tym wartości odżywczej żywności. Wiąże się to z koniecznością zmian w procesach produkcji, co w efekcie ma usatysfakcjonować jak największą liczbę konsumentów. Błonnik pokarmowy jest przykładem składnika wzbogacającego środki spożywcze, który w ostatnim czasie jest przedmiotem wzmożonego zainteresowania zarówno ze strony producentów, jak i konsumen- tów, którzy uznają go przede wszystkim za prozdrowotny składnik żywności. W ubiegłym wieku stoso- wanie dodatku błonnika pokarmowego do żywności bardzo często wiązało się z powstawaniem nieko- rzystnej tekstury produktu. Obecnie produkowane są nowoczesne preparaty błonnikowe, które korzystnie wpływają na teksturę, właściwości funkcjonalne oraz sensoryczne żywności i charakteryzują się takimi właściwościami, jak: wiązanie wody, zwiększanie objętości produktów, neutralny zapach oraz smak czy możliwość stosowania jako zamiennika tłuszczu. W pracy omówiono historię i podział żywności funkcjonalnej, definicję i podział błonnika pokarmo- wego oraz możliwości zastosowania tego składnika w projektowaniu i wzbogacaniu produktów żywno- ściowych

Production of hydrogen using solar-powered electrolysis

A solar-powered electrolysis (SPE) unit was modelled to provide 58,400 kg of hydrogen to run the fuel cell bus fleet in Lea interchange garage in London on a yearly basis. Experiments were conducted to determine the efficiency of the photovoltaic (PV) module and the electrolyser. An energy balance of the electrolysis unit was calculated to give 47.82 kwh/kg and used to model a 2.98 MW photovoltaic system required to run the electrolysis process. Cost analysis was conducted to show that steam methane reforming cost £1.14/kg while solar-powered electrolysis cost £15.76/kg of hydrogen gas