I···N Halogen bonding in 1:1 co-crystals formed between 1,4-diiodotetrafluorobenzene and the isomeric n-pyridinealdazines (n = 2, 3 and 4): Assessment of supramolecular association and influence upon solid-state photoluminescence properties

1:1 Co-crystals formed between 1,4-diiodotetrafluorobenzene and each of the three isomeric npyridinealdazines (n = 2, 3 and 4) have been characterised by X-ray crystallography, a variety of spectroscopic methods, viz. IR, Raman, NMR: solution- and solid-state (13C CP MAS and 13C HPDEC MAS) and fluorescence as well as by computational chemistry techniques. The primary connection between the respective coformers arises from I···N halogen bonds which give rise to one-dimensional supramolecular chains of varying topology depending on the position of the nitrogen atom in the n-pyridinealdazine isomer. The energies calculated for the I···N contacts are relatively small, varying from -5.4 to -6.3 kcal/mol, with the maximum being in the crystal of the 2 n = 3 isomer. Notable in the molecular packing are C-I···π(pyridine) and C–F···π(arene) interactions in the crystals with the 3- and 4-pyridinealdazine coformers, respectively. The cocrystal formed by 2-pyridinealdazine exhibited fluorescence emission

Morindone from Morinda citrifolia as a potential antiproliferative agent against colorectal cancer cell lines

There is an increasing demand in developing new, effective, and affordable anti-cancer against colon and rectal. In this study, our aim is to identify the potential anthraquinone compounds from the root bark of Morinda citrifolia to be tested in vitro against colorectal cancer cell lines. Eight potential anthraquinone compounds were successfully isolated, purified and tested for both in-silico and in-vitro analyses. Based on the in-silico prediction, two anthraquinones, morindone and rubiadin, exhibit a comparable binding affinity towards multitargets of β-catenin, MDM2-p53 and KRAS. Subsequently, we constructed a 2D interaction analysis based on the above results and it suggests that the predicted anthraquinones from Morinda citrifolia offer an attractive starting point for potential antiproliferative agents against colorectal cancer. In vitro analyses further indicated that morindone and damnacanthal have significant cytotoxicity effect and selectivity activity against colorectal cancer cell lines

Molecular Modeling of Peroxidase and Polyphenol Oxidase: Substrate Specificity and Active Site Comparison

Peroxidases (POD) and polyphenol oxidase (PPO) are enzymes that are well known to be involved in the enzymatic browning reaction of fruits and vegetables with different catalytic mechanisms. Both enzymes have some common substrates, but each also has its specific substrates. In our computational study, the amino acid sequence of grape peroxidase (ABX) was used for the construction of models employing homology modeling method based on the X-ray structure of cytosolic ascorbate peroxidase from pea (PDB ID:1APX), whereas the model of grape polyphenol oxidase was obtained directly from the available X-ray structure (PDB ID:2P3X). Molecular docking of common substrates of these two enzymes was subsequently studied. It was found that epicatechin and catechin exhibited high affinity with both enzymes, even though POD and PPO have different binding pockets regarding the size and the key amino acids involved in binding. Predicted binding modes of substrates with both enzymes were also compared. The calculated docking interaction energy of trihydroxybenzoic acid related compounds shows high affinity, suggesting specificity and potential use as common inhibitor to grape ascorbate peroxidase and polyphenol oxidase

Resistance to the “Last Resort” Antibiotic Colistin:A Single-Zinc Mechanism for Phosphointermediate Formation in MCR Enzymes

MCR (mobile colistin resistance) enzymes catalyse phosphoethanolamine (PEA) addition to bacterial lipid A, threatening the “last-resort” antibiotic colistin. Molecular dynamics and density functional theory simulations indicate that monozinc MCR supports PEA transfer to the Thr285 acceptor, positioning MCR as a mono- rather than multinuclear member of the alkaline phosphatase superfamily.Mahidol University (Thailand)University of BristolThailand Research FundMedical Research CouncilUniversiti Malaya (Malaysia)Research EnglandRoyal Society of ChemistryDepto. de Química FísicaFac. de Ciencias QuímicasTRUEpu

Substitution of Coxsackievirus A16 VP1 BC and EF Loop Altered the Protective Immune Responses in Chimera Enterovirus A71

Hand, foot and mouth disease (HFMD) is a childhood disease caused by enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16). Capsid loops are important epitopes for EV-A71 and CV-A16. Seven chimeric EV-A71 (ChiE71) involving VP1 BC (45.5% similarity), DE, EF, GH and HI loops, VP2 EF loop and VP3 GH loop (91.3% similarity) were substituted with corresponding CV-A16 loops. Only ChiE71-1-BC, ChiE71-1-EF, ChiE71-1-GH and ChiE71-3-GH were viable. EV-A71 and CV-A16 antiserum neutralized ChiE71-1-BC and ChiE71-1-EF. Mice immunized with inactivated ChiE71 elicited high IgG, IFN-γ, IL-2, IL-4 and IL-10. Neonatal mice receiving passive transfer of WT EV-A71, ChiE71-1-EF and ChiE71-1-BC immune sera had 100%, 80.0% and no survival, respectively, against lethal challenges with EV-A71, suggesting that the substituted CV-A16 loops disrupted EV-A71 immunogenicity. Passive transfer of CV-A16, ChiE71-1-EF and ChiE71-1-BC immune sera provided 40.0%, 20.0% and 42.9% survival, respectively, against CV-A16. One-day-old neonatal mice immunized with WT EV-A71, ChiE71-1-BC, ChiE71-1-EF and CV-A16 achieved 62.5%, 60.0%, 57.1%, and no survival, respectively, after the EV-A71 challenge. Active immunization using CV-A16 provided full protection while WT EV-A71, ChiE71-1-BC and ChiE71-1-EF immunization showed partial cross-protection in CV-A16 lethal challenge with survival rates of 50.0%, 20.0% and 40%, respectively. Disruption of a capsid loop could affect virus immunogenicity, and future vaccine design should include conservation of the enterovirus capsid loops

Ternary glycerol-based deep eutectic solvents: physicochemical properties and enzymatic activity

The present study investigates deep eutectic solvents (DESs) as potential media for enzymatic hydrolysis. A series of ternary ammonium and phosphonium-based DESs were prepared at different molar ratios by mixing with aqueous glycerol (85%). The physicochemical properties including surface tension, conductivity, density, and viscosity were measured at a temperature range of 298.15 K – 363.15 K. The eutectic points were highly influenced by the variation of temperature. The eutectic point of the choline chloride: glycerol: water (ratio of 1: 2.55: 2.28) and methyl triphenylphosphonium bromide:glycerol: water (ratio of 1: 4.25:3.75) is 213.4 K and 255.8 K, respectively. The stability of the lipase enzyme isolated from the porcine pancreas (PPL) and Rhizopus niveus (RNL) toward hydrolysis in ternary DESs medium was investigated. The PPL showed higher activity compared to the RNL in DESs. Molecular docking simulation of the selected DES with the substrate (p-nitrophenyl palmitate) towardPPL was also reported. It is worth noting that ternary DES systems would be viable lipaseactivators in hydrolysis reactions

Chemical Reaction of Soybean Flavonoids with DNA: A Computational Study Using the Implicit Solvent Model

Genistein, daidzein, glycitein and quercetin are flavonoids present in soybean and other vegetables in high amounts. These flavonoids can be metabolically converted to more active forms, which may react with guanine in the DNA to form complexes and can lead to DNA depurination. We assumed two ultimate carcinogen forms of each of these flavonoids, diol epoxide form and diketone form. Density functional theory (DFT) and Hartree-Fock (HF) methods were used to study the reaction thermodynamics between active forms of flavonoids and DNA guanine. Solvent reaction field method of Tomasi and co-workers and the Langevin dipoles method of Florian and Warshel were used to calculate the hydration free energies. Activation free energy for each reaction was estimated using the linear free energy relation. Our calculations show that diol epoxide forms of flavonoids are more reactive than the corresponding diketone forms and are hence more likely flavonoid ultimate carcinogens. Genistein, daidzein and glycitein show comparable reactivity while quercetin is less reactive toward DNA