Molecular Mechanism of pH-Induced Protrusion Configuration Switching in Piscine Betanodavirus Implies a Novel Antiviral Strategy.

Many viruses contain surface spikes or protrusions that are essential for virus entry. These surface structures can thereby be targeted by antiviral drugs to treat viral infections. Nervous necrosis virus (NNV), a simple nonenveloped virus in the genus of betanodavirus, infects fish and damages aquaculture worldwide.

Lithium-Ion Dynamic and Storage of Atomically Precise Halogenated Nanographene Assemblies via Bottom-Up Chemical Synthesis.

Graphene has received much scientific attention as an electrode material for lithium-ion batteries because of its extraordinary physical and electrical properties. However, the lack of structural control and restacking issues have hindered its application as carbon-based anode materials for next generation lithium-ion batteries. To improve its performance, several modification approaches such as edge-functionalization and electron-donating/withdrawing substitution have been considered as promising strategies.

A Facile NMR Method for Pre-MRI Evaluation of Trigger-Responsive T Contrast Enhancement.

There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T image contrast of water protons upon biochemical cues for better discerning diseases. However, performing an MRI is pragmatically limited by its cost and availability. Hence, a facile, routine method for measuring the T contrast is highly desired in early-stage development.

Structural and functional analyses of viral H2 protein of the vaccinia virus entry fusion complex.

Vaccinia virus infection requires virus-cell membrane fusion to complete entry during endocytosis; however, it contains a large viral fusion protein complex of 11 viral proteins that share no structure or sequence homology to all the known viral fusion proteins, including type I, II, and III fusion proteins. It is thus very challenging to investigate how the vaccinia fusion complex works to trigger membrane fusion with host cells. In this study, we crystallized the ectodomain of vaccinia H2 protein, one component of the viral fusion complex.

Structural and functional analysis of vaccinia viral fusion complex component protein A28 through NMR and molecular dynamic simulations.

Host cell entry of vaccinia virus (a poxvirus) proceeds through multiple steps that involve many viral proteins to mediate cell infection. Upon binding to cells, vaccinia virus membrane fuses with host membranes via a viral entry fusion protein complex comprising 11 proteins: A16, A21, A28, F9, G3, G9, H2, J5, L1, L5 and O3. Despite vaccinia virus having two infectious forms, mature and enveloped, that have different membrane layers, both forms require an identical viral entry fusion complex for membrane fusion.

Stable Crystalline Organic-Inorganic Hybrid Indium Phosphate with Dye Removal and Ractopamine Detection Applications.

A highly stable framework of an organic-inorganic hybrid indium phosphate () was synthesized under hydro(solvo)thermal conditions and structurally characterized by single-crystal X-ray diffraction and solid-state NMR spectroscopy. This is the first example of a post-transition-metal phosphate incorporating tetradentate organic molecules. The In atoms in the inorganic layers are coordinated by imidazole rings of the 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene linkers to generate a new solid-state material.

Resolving Entangled -Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy.

For decades, high-resolution H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the H signals are inevitably superimposed and entangled with various splitting patterns, such that the individual H chemical shift and associated coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted.

NMR assignments of vaccinia virus protein A28: an entry-fusion complex component.

Vaccinia virus (VACV) belonging to the poxvirus family enters the host cell via two different entry pathways; either endocytosis or virus/host cell membrane fusion. With respect to the virus/host cell membrane fusion, there are eleven viral membrane proteins forming a complicated entry-fusion complex (EFC), including A28, A21, A16, F9, G9, G3, H2, J5, L5, L1 and O3, to conduct the fusion function. These EFC components are highly conserved in all poxviruses and each of them is essential and necessary for the fusion activity.

The Effect of Calcium and Halide Ions on the Gramicidin A Molecular State and Antimicrobial Activity.

Gramicidin A (gA) forms several convertible conformations in different environments. In this study, we investigated the effect of calcium halides on the molecular state and antimicrobial activity of gramicidin A. The molecular state of gramicidin A is highly affected by the concentration of calcium salt and the type of halide anion.

NMR assignments of protrusion domain of capsid protein from dragon grouper nervous necrosis virus.

Nervous necrosis virus (NNV) is a non-enveloped virus that causes massive mortality in aquaculture fish production worldwide. Recently X-ray crystallography and single particle cryo-EM have independently determined the icosahedral capsid of NNV to near-atomic resolutions to show the capsid protein is composed of a S-domain (shell) and a P-domain (protrusion) connected by a linker. However, the structure of the spike on NNV capsid made of trimeric P-domains was poorly resolved by cryo-EM.

H/C chemical shifts and cation binding dataset of the corticosteroid Prednisolone titrated with metal cations.

We here reported the H/C chemical shifts, binding affinity and binding free energy of 1,4-pregnadiene-11β,17α,21-triol-3,20-dione (Prednisolone; Prd) interacting with metal cations. Six different Prd/Ni or Co mixtures were examined at different molar ratios (1:0, 1:0.1, 1:0.

Magnesium and calcium reveal different chelating effects in a steroid compound: A model study of prednisolone using NMR spectroscopy.

In this work, we used high resolution NMR spectroscopy to investigate metal cation chelation by the steroidal drug 1,4-pregnadiene-11β,17α,21-triol-3,20-dione (Prednisolone; abbreviated as Prd). Prd/MgCl and Prd/CaCl mixtures were prepared at eight different molar ratios. Using two-dimensional H/C heteronuclear correlation spectroscopy, we were able to resolve most of the H signals, except those at 1.

Vaccinia viral A26 protein is a fusion suppressor of mature virus and triggers membrane fusion through conformational change at low pH.

Vaccinia mature virus requires A26 envelope protein to mediate acid-dependent endocytosis into HeLa cells in which we hypothesized that A26 protein functions as an acid-sensitive membrane fusion suppressor. Here, we provide evidence showing that N-terminal domain (aa1-75) of A26 protein is an acid-sensitive region that regulates membrane fusion. Crystal structure of A26 protein revealed that His48 and His53 are in close contact with Lys47, Arg57, His314 and Arg312, suggesting that at low pH these His-cation pairs could initiate conformational changes through protonation of His48 and His53 and subsequent electrostatic repulsion.

NMR investigation of magnesium chelation and cation-induced signal shift effect of testosterone.

We have previously reported that testosterone (Tes) is able to interact with magnesium chloride dissolved in methanol. In this study, we have applied H and C NMR spectroscopies to a series of Tes solutions containing Mg at various concentrations. High-resolution C NMR spectra of Tes/Mg revealed well-resolved C signals, and the intensities of those arising from C3, C5, C16, and C17 decreased linearly with increasing Mg concentration.

Solid-state NMR investigation of effect of fluorination and methylation on prednisolone conformation.

Prednisolone (Prd) is a polymorphous synthetic corticosteroid that has three crystalline forms mediated by different solvents. In this study, we have demonstrated that solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy is able to resolve the effects of methylation and fluorination on the conformation of the steroidal rings in Prd. Two compounds were chosen for the study, 6-α-methylprednisolone (Prd-6M) and 6-α-fluoroprednisolone (Prd-6F).

Monodispersity of magnetic immuno-nanoprobes enhances the detection sensitivity of low abundance biomarkers in one drop of serum.

To enhance the detection sensitivity of target clinical protein biomarkers, a simple and rapid nanoprobe-based immuno-affinity mass spectrometry assay employing biocompatible monodisperse magnetic nanoparticles (MNPs) is reported herein. The MNPs were synthesized via a streamlined protocol that includes (a) fabrication of core MNPs using the thermal decomposition method to minimize aggregation, (b) surface protection by gold coating (MNP@Au) and surfactant coating using MNP@IGEPAL to improve hydrophilicity, and lastly, (c) oriented functionalization of antibodies to maximize immuno-affinity. The enrichment performances of the monodisperse MNPs for the C-reactive protein (CRP) serum biomarker were then evaluated and compared with aggregated magnetic nanoparticles synthesized from the conventional co-precipitation method (MNP(CP)).

Cation ion specifically induces a conformational change in trans-dehydroandrosterone - a solid-state NMR study.

In this work, we demonstrated that calcium (Ca(+2)) is able to induce a conformational change in trans-dehydroandrosterone (DHEA). To this respect, solid-state NMR spectroscopy was applied to a series of DHEA molecules that were incubated with Ca(+2) under different concentrations. The high-resolution (13)C NMR spectra of the DHEA/Ca(+2) mixtures exhibited two distinct sets of signals; one was attributed to DHEA in the free form, and the second set was due to the DHEA/Ca(+2) complex.

Vaccinia viral protein A27 is anchored to the viral membrane via a cooperative interaction with viral membrane protein A17.

The vaccinia viral protein A27 in mature viruses specifically interacts with heparan sulfate for cell surface attachment. In addition, A27 associates with the viral membrane protein A17 to anchor to the viral membrane; however, the specific interaction between A27 and A17 remains largely unclear. To uncover the active binding sites and the underlying binding mechanism, we expressed and purified the N-terminal (18-50 residues) and C-terminal (162-203 residues) fragments of A17, which are denoted A17-N and A17-C.

Solid-state NMR study of fluorinated steroids.

Solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy was performed to analyze two fluorinated steroids, i.e., betamethasone (BMS) and fludrocortisone acetate (FCA), that have fluorine attached to C9, as well as two non-fluorinated analogs, i.

Stepwise orthogonal click chemistry toward fabrication of paclitaxel/galactose functionalized fluorescent nanoparticles for HepG2 cell targeting and delivery.

In this report, we used stepwise orthogonal click chemistry (SOCC) involving strain-promoted azide-alkyne cycloaddition (SPAAC) and microwave-assisted Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) to assemble an anticancer drug (paclitaxel, PTX) and a targeting ligand (trivalent galactoside, TGal) on a fluorescent silicon oxide nanoparticle (NP) by using dialkyne linker 8 as a bridge. The fluorescent NH2@Cy3SiO2NP was fabricated using a competition method to incorporate Cy3 without loss of the original surface amine density on the NPs. The concept of SOCC was first investigated in a solution-phase model study that showed quantitative reaction yield.

¹H, ¹³C and ¹⁵N backbone and side-chain resonance assignments of a family 36 carbohydrate binding module of xylanase from Paenibacillus campinasensis.

Paenibacillus campinasensis BL11 isolated from black liquor secretes multiple glycoside hydrolases (GHs) against all kinds of polysaccharides. GH consists of a catalytic module and non-catalytic carbohydrate-binding modules (CBMs), in which CBMs append to the catalytic module, mediating specific interactions with insoluble carbohydrates to promote the hydrolysis efficiency of the cognate enzyme. Endo-β-1,4-xylanase (XylX) is one of the GHs reveals high enzymatic activity in a wide range of pH and thermal endurance, suitable for bioconversion and bio-refinement applications.

Bandwidth in double cross-polarization MAS NMR spectroscopy.

The signal intensity in double cross-polarization (DCP) NMR experiments is critically dependent on the experimental parameters, which include the rf field strength, carrier frequency, and magic-angle spinning (MAS) frequency. In this systematic study, we have monitored {(1)H}/(31)P/(13)C DCP signals from monosaccharide α-D-[UL-(13)C(6)] galactopyranosyl 1-phosphate (GalP) at a MAS frequency of 13 kHz, at which only double quantum cross-polarization (CP) coherence transfer is allowed. To lessen the stringent requirements for these experimental parameters, we have implemented linear ramp pulse, adiabatic ramp-shaped pulse, and block pulse during the period of (31)P/(13)C CP.

Solid-state NMR analysis of steroidal conformation of 17α- and 17β-estradiol in the absence and presence of lipid environment.

Solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy has been applied to 17β-estradiol (E2) and 17α-estradiol (E2α), to analyze the steroidal ring conformations of the two isomers in the absence and presence of lipids at the atomic level. In the absence of lipid, the high-resolution (13)C NMR signals of E2 in a powdered form show only singlet patterns, suggesting a single ring conformation. In contrast, the (13)C signals of E2α reveal multiplet patterns with splittings of 20-300Hz, implying multiple ring conformations.