Biological activities and 3D QSAR studies of a series of Delisea pulchra (cf. fimbriata) derived natural products.

Twenty-five natural products, mainly halogenated furanones, isolated from the temperate red algae Delisea pulchra were investigated for their cytotoxic, antimicrobial, and antiplasmodial effects, their inhibition of the activity of the enzymes HIV-1-RT (HIV-1-reverse transcriptase), PKC (protein kinase C), and TK (tyrosine kinase), and their inhibition of the biosynthesis of IL-1 (interleukin-1). All were found to mediate a positive response in one or more of these test systems. In particular, compounds 9, 11, 12, 14, 16, 17, 19, and 20 demonstrated cytotoxic activity in all of the assays they were tested in; compounds 11, 12, 17, 19, and 20 were also active in the majority of the anti-infective screens.

Structure-activity relationships of seco-prezizaane and picrotoxane/picrodendrane terpenoids by Quasar receptor-surface modeling.

The seco-prezizaane-type sesquiterpenes pseudoanisatin and parviflorolide from Illicium are noncompetitive antagonists at housefly (Musca domestica) gamma-aminobutyric acid (GABA) receptors. They show selectivity toward the insect receptor and thus represent new leads toward selective insecticides. Based on the binding data for 13 seco-prezizaane terpenoids and 17 picrotoxane and picrodendrane-type terpenoids to housefly and rat GABA receptors, a QSAR study was conducted by quasi-atomistic receptor-surface modeling (Quasar).

Adjacent cysteines are capable of ligating the same tetranuclear iron-sulfur cluster.

The mechanism of the energy-converting NADH (beta-nicotinamide adenine dinucleotide, reduced form):ubiquinone oxidoreductase, which is also called respiratory complex I, is largely unknown due to lack of a high-resolution structure and the most complicated construction of the enzyme. Electron transport is carried out by one flavin mononucleotide (FMN) and up to 9 Fe/S clusters. The Fe/S cluster N2, which is believed to be directly involved in redox-coupled proton-translocation, is located on subunit NuoB (the homologue of the mitochondrial PSST subunit).

Molecular modelling studies on the ORL1-receptor and ORL1-agonists.

The ORLI (opioid receptor like 1)- receptor is a member of the family of rhodopsin-like G protein-coupled receptors (GPCR) and represents an interesting new therapeutical target since it is involved in a variety of biomedical important processes, such as anxiety, nociception, feeding, and memory. In order to shed light on the molecular basis of the interactions of the GPCR with its ligands, the receptor protein and a dataset of specific agonists were examined using molecular modelling methods. For that purpose, the conformational space of a very potent non-peptide ORL1-receptor agonist (Ro 64-6198) with a small number of rotatable bonds was analysed in order to derive a pharmacophoric arrangement.