The T structure of polycrystalline cubic human insulin.

The polymorphism of human insulin upon pH variation was characterized via X-ray powder diffraction, employing a crystallization protocol previously established for co-crystallization with phenolic derivatives. Two distinct rhombohedral (R3) polymorphs and one cubic (I23) polymorph were identified with increasing pH, corresponding to the T, TR and T conformations of insulin, respectively. The structure of the cubic T polymorph was determined via multi-profile stereochemically restrained Rietveld refinement at 2.

Methods on LDL particle isolation, characterization, and component fractionation for the development of novel specific oxidized LDL status markers for atherosclerotic disease risk assessment.

The present study uses simple, innovative methods to isolate, characterize and fractionate LDL in its main components for the study of specific oxidations on them that characterize oxidized low-density lipoprotein (oxLDL) status, as it causatively relates to atherosclerosis-associated cardiovascular disease (CVD) risk assessment. These methods are: (a) A simple, relatively time-short, low cost protocol for LDL isolation, to avoid shortcomings of the currently employed ultracentrifugation and affinity chromatography methodologies. (b) LDL purity verification by apoB100 SDS-PAGE analysis and by LDL particle size determination; the latter and its serum concentration are determined in the present study by a simple method more clinically feasible as marker of CVD risk assessment than nuclear magnetic resonance.

New perspectives in macromolecular powder diffraction using single-photon-counting strip detectors: high-resolution structure of the pharmaceutical peptide octreotide.

Advances in instrumentation, as well as the development of powerful crystallographic software have significantly facilitated the collection of high-resolution diffraction data and have made X-ray powder diffraction (XRPD) particularly useful for the extraction of structural information; this is true even for complex molecules, especially when combined with synchrotron radiation. In this study, in-line with past instrumental profile studies, an improved data collection strategy exploiting the MYTHEN II detector system together with significant beam focusing and tailored data collection options was introduced and optimized for protein samples at the Material Science beamline at the Swiss Light Source. Polycrystalline precipitates of octreotide, a somatostatin analog of particular pharmaceutical interest, were examined with this novel approach.

Insulin polymorphism induced by two polyphenols: new crystal forms and advances in macromolecular powder diffraction.

This study focuses on the polymorphism of human insulin (HI) upon the binding of the phenolic derivatives p-coumaric acid or trans-resveratrol over a wide pH range. The determination of the structural behaviour of HI via X-ray powder diffraction (XRPD) and single-crystal X-ray diffraction (SCXRD) is reported. Four distinct polymorphs were identified, two of which have not been reported previously.

Rapid screening of grown protein crystals via a small-angle X-ray scattering/X-ray powder diffraction synergistic approach.

Crystallization of recombinant proteins in living cells is an exciting new approach for structural biology that provides an alternative to the time-consuming optimization of protein purification and extensive crystal screening steps. Exploiting the potential of this approach requires a more detailed understanding of the cellular processes involved and versatile screening strategies for crystals in a cell culture. Particularly if the target protein forms crystalline structures of unknown morphology only in a small fraction of cells, their detection by applying standard visualization techniques can be time consuming and difficult owing to the environmental challenges imposed by the living cells.

Revisiting the structure of a synthetic somatostatin analogue for peptide drug design.

Natural or artificially manufactured peptides attract scientific interest worldwide owing to their wide array of pharmaceutical and biological activities. X-ray structural studies are used to provide a precise extraction of information, which can be used to enable a better understanding of the function and physicochemical characteristics of peptides. Although it is vulnerable to disassociation, one of the most vital human peptide hormones, somatostatin, plays a regulatory role in the endocrine system as well as in the release of numerous secondary hormones.

Brothers in Arms: Structure, Assembly and Function of Nucleoprotein.

is a family of viruses harbouring important emerging pathogens belonging to the order. Like in other segmented negative strand RNA viruses, the nucleoprotein (NP) is a major actor of the viral life cycle being both (i) the necessary co-factor of the polymerase present in the L protein, and (ii) the last line of defence of the viral genome (vRNA) by physically hiding its presence in the cytoplasm. The NP is also one of the major players interfering with the immune system.

In Quest for Improved Drugs against Diabetes: The Added Value of X-ray Powder Diffraction Methods.

Human insulin (HI) is a well-characterized natural hormone which regulates glycose levels into the blood-stream and is widely used for diabetes treatment. Numerous studies have manifested that despite significant efforts devoted to structural characterization of this molecule and its complexes with organic compounds (ligands), there is still a rich diagram of phase transitions and novel crystalline forms to be discovered. Towards the improvement of drug delivery, identification of new insulin polymorphs from polycrystalline samples, simulating the commercially available drugs, is feasible today via macromolecular X-ray powder diffraction (XRPD).

Dynamic versus Static Character of the Magnetic Jahn-Teller Effect: Magnetostructural Studies of [FeO(OCPh)(py)]ClO·py.

Complex [FeO(OCPh)(py)]ClO·py (1) crystallizes in the hexagonal P6/m space group, and its cation exhibits a crystallographically imposed D symmetry due to a C axis passing through the oxide of its {FeO} core. Single-crystal unit-cell studies carried out with synchrotron radiation confirmed that this symmetry is retained down to 4.5 K; a full crystal structure determination carried out at 90 K resolved the previously reported disorder of the perchlorate anion.

Macromolecular Powder Diffraction: Ready for genuine biological problems.

Knowledge of 3D structures of biological molecules plays a major role in both understanding important processes of life and developing pharmaceuticals. Among several methods available for structure determination, macromolecular X-ray powder diffraction (XRPD) has transformed over the past decade from an impossible dream to a respectable method. XRPD can be employed in biosciences for various purposes such as observing phase transitions, characterizing bulk pharmaceuticals, determining structures via the molecular replacement method, detecting ligands in protein-ligand complexes, as well as combining micro-sized single crystal crystallographic data and powder diffraction data.

Evidence for photochemical production of reactive oxygen species in desert soils.

The combination of intense solar radiation and soil desiccation creates a short circuit in the biogeochemical carbon cycle, where soils release significant amounts of CO2 and reactive nitrogen oxides by abiotic oxidation. Here we show that desert soils accumulate metal superoxides and peroxides at higher levels than non-desert soils. We also show the photogeneration of equimolar superoxide and hydroxyl radical in desiccated and aqueous soils, respectively, by a photo-induced electron transfer mechanism supported by their mineralogical composition.

NMR study of non-structural proteins--part I: (1)H, (13)C, (15)N backbone and side-chain resonance assignment of macro domain from Mayaro virus (MAYV).

Macro domains are ADP-ribose-binding modules present in all eukaryotic organisms, bacteria and archaea. They are also found in non-structural proteins of several positive strand RNA viruses such as alphaviruses. Here, we report the high yield expression and preliminary structural analysis through solution NMR spectroscopy of the macro domain from New World Mayaro Alphavirus.

High-resolution powder X-ray data reveal the T(6) hexameric form of bovine insulin.

A series of bovine insulin samples were obtained as 14 polycrystalline precipitates at room temperature in the pH range 5.0-7.6.

Structural studies of human insulin cocrystallized with phenol or resorcinol via powder diffraction.

The effects of the ligands phenol and resorcinol on the crystallization of human insulin have been investigated as a function of pH. Powder diffraction data were used to characterize several distinct polymorphic forms. A previously unknown polymorph with monoclinic symmetry (P2(1)) was identified for both types of ligand with similar characteristics [the unit-cell parameters for the insulin-resorcinol complex were a = 114.

Features of the secondary structure of a protein molecule from powder diffraction data.

Protein powder diffraction is shown to be suitable for obtaining de novo solutions to the phase problem at low resolution via phasing methods such as the isomorphous replacement method. Two heavy-atom derivatives (a gadolinium derivative and a holmium derivative) of the tetragonal form of hen egg-white lysozyme were crystallized at room temperature. Using synchrotron radiation, high-quality powder patterns were collected in which pH-induced anisotropic lattice-parameter changes were exploited in order to reduce the challenging and powder-specific problem of overlapping reflections.

Synthesis, structure, and catalytic performance in cyclooctene epoxidation of a molybdenum oxide/bipyridine hybrid material: {[MoO3(bipy)][MoO3(H2O)]}n.

The reaction of [MoO(2)Cl(2)(bipy)] (1) (bipy = 2,2'-bipyridine) with water in a Teflon-lined stainless steel autoclave (100 degrees C, 19 h), in an open reflux system with oil bath heating (12 h) or in a microwave synthesis system (120 degrees C, 4 h), gave the molybdenum oxide/bipyridine hybrid material {[MoO(3)(bipy)][MoO(3)(H(2)O)]}(n) (2) as a microcrystalline powder in yields of 72-92%. The crystal structure of 2 determined from synchrotron X-ray powder diffraction data is composed of two distinct neutral one-dimensional polymers: an organic-inorganic polymer, [MoO(3)(bipy)](n), and a purely inorganic chain, [MoO(3)(H(2)O)](n), which are interconnected by O-H..

Yttrium bisphosphonate STA-13: a racemic phosphonate metal organic framework with permanent microporosity.

Crystallisation of yttrium and other trivalent metal cations of similar radius with racemic N,N'-2-methylpiperazinebis(methylene phosphonic acid) gives a small pore bisphosphonate metal-organic framework solid displaying coordinative and hydrogen bonding and permanent porosity.

Polymorphism of microcrystalline urate oxidase from Aspergillus flavus.

Different polymorphs of rasburicase, a recombinant urate oxidase enzyme (Uox) from Aspergillus flavus, were obtained as a series of polycrystalline precipitates. Different crystallization protocols were followed in which the salt type, pH and polyethylene glycol 8000 (PEG 8000) concentration were varied. The related crystalline phases were characterized by means of high-resolution synchrotron X-ray powder diffraction.

[Al4(OH)2(OCH3)4(H2N-bdc)3] x xH(2)O: a 12-connected porous metal-organic framework with an unprecedented aluminum-containing brick.

Al together now! A new stable aluminum aminoterephthalate system contains octameric building blocks that are connected by organic linkers to form a 12-connected net (see picture). The structure adopts a cubic centered packing motive in which octameric units replace individual atoms, thus forming distorted octahedral (red sphere) and tetrahedral cages (green spheres) with effective accessible diameters of 1 and 0.45 nm, respectively.

Structural Transformations and adsorption of fuel-related gases of a structurally responsive nickel phosphonate metal-organic framework, Ni-STA-12.

The structure of the nickel N,N'-piperazinebismethylenephosphonate, Ni-STA-12 (St. Andrews porous material-12), has been determined in the hydrated (Ni2L x 8 H2O, L = O3PCH2NC4H8NCH2PO3), partially dehydrated (Ni2L x 2 H2O), and fully dehydrated (Ni2L) forms from high-resolution synchrotron X-ray powder diffraction. The framework structures of Ni2L x 8 H2O and Ni2L x 2 H2O are almost identical (R, a = 27.

Effect of the nature of the metal on the breathing steps in MOFs with dynamic frameworks.

The thermal behaviour of the nanoporous iron(iii) terephthalate MIL-53 is in stark contrast to its chromium and aluminium analogues which show an expansion of the cell during dehydration; with iron, reversible dehydration occurs via evolution of the structure through a highly distorted metastable anhydrous phase to a more regular phase above 423 K in which pore volume remains approximately constant.

Second SH3 domain of ponsin solved from powder diffraction.

Determination of protein crystal structures is dependent on the growth of high-quality single crystals, a process that is not always successful. Optimum crystallization conditions must be systematically sought for, and microcrystalline powders are frequently obtained in failed attempts to grow the desired crystal. In materials science, structures of samples ranging from ceramics, pharmaceuticals, zeolites, etc.

Synthesis and catalytic properties of MIL-100(Fe), an iron(III) carboxylate with large pores.

The large-pore iron(III) carboxylate MIL-100(Fe) with a zeotype architecture has been isolated under hydrothermal conditions, its structure solved from synchrotron X-ray powder diffraction data, while Friedel-Crafts benzylation catalytic tests indicate a high activity and selectivity for MIL-100(Fe).