Chemosensory protein from the moth Mamestra brassicae. Expression and secondary structure from 1H and 15N NMR.

A group of ubiquitous small proteins (average 13 kDa) has been isolated from several sensory organs of a wide range of insect species. They are believed to be involved in chemical communication and perception (olfaction or taste) and have therefore been called chemo-sensory proteins (CSPs). Several CSPs have been identified in the antennae and proboscis of the moth Mamestra brassicae.

Complexation of two proteic insect inhibitors to the active site of chymotrypsin suggests decoupled roles for binding and selectivity.

The crystal structures of two homologous inhibitors (PMP-C and PMP-D2v) from the insect Locusta migratoria have been determined in complex with bovine alpha-chymotrypsin at 2.1- and 3.0-A resolution, respectively.

Lateral recognition of a dye hapten by a llama VHH domain.

Camelids, camels and llamas, have a unique immune system able to produce heavy-chain only antibodies. Their VH domains (VHHs) are the smallest binding units produced by immune systems, and therefore suitable for biotechnological applications through heterologous expression. The recognition of protein antigens by these VHHs is rather well documented, while less is known about the VHH/hapten interactions.

Streptomyces matensis laminaripentaose hydrolase is an 'inverting' beta-1,3-glucanase.

The laminaripentaose-producing beta-1,3-glucanase of Streptomyces matensis is a member of the glycoside hydrolase family GH-64. We have constructed and purified a recombinant hexahistidine-tagged form of the enzyme for characterisation. The enzyme, which exists as a monomer in solution, hydrolyses beta-1,3-glucan by a mechanism leading to overall inversion of the anomeric configuration.

An integrated system to study multiply substituted human immunodeficiency virus type 1 reverse transcriptase.

We describe a gene system allowing the facile production of multiply substituted reverse transcriptases (RTs), the enzymatic characterization of these purified RTs, and the study of these mutations in the defined genetic background of the macrophagetropic, non-laboratory-adapted human immunodeficiency virus type 1 (HIV-1) AD8 strain. Thirteen unique silent restriction sites were introduced in the pol gene encoding HIV-1 RT, allowing easy introduction of mutations. To simplify genetic manipulation and generate p66/p51 heterodimers in Escherichia coli, a gene construct of the viral protease alone was optimized for expression from a separate vector carrying a p15A origin of replication.

Revisiting the specificity of Mamestra brassicae and Antheraea polyphemus pheromone-binding proteins with a fluorescence binding assay.

Pheromone-binding proteins (PBPs), located in the sensillum lymph of pheromone-responsive antennal hairs, are thought to transport the hydrophobic pheromones to the chemosensory membranes of olfactory neurons. It is currently unclear what role PBPs may play in the recognition and discrimination of species-specific pheromones. We have investigated the binding properties and specificity of PBPs from Mamestra brassicae (MbraPBP1), Antheraea polyphemus (ApolPBP1), Bombyx mori (BmorPBP), and a hexa-mutant of MbraPBP1 (Mbra1-M6), mutated at residues of the internal cavity to mimic that of BmorPBP, using the fluorescence probe 1-aminoanthracene (AMA).

Bovine alpha1,3-galactosyltransferase catalytic domain structure and its relationship with ABO histo-blood group and glycosphingolipid glycosyltransferases.

alpha1,3-galactosyltransferase (alpha3GalT, EC 2.4.1.

Crystal structure of a monocotyledon (maize ZMGlu1) beta-glucosidase and a model of its complex with p-nitrophenyl beta-D-thioglucoside.

The maize beta-glucosidase isoenzymes ZMGlu1 and ZMGlu2 hydrolyse the abundant natural substrate DIMBOAGlc (2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one), whose aglycone DIMBOA (2,4-hydroxy-7-methoxy-1,4-benzoxazin-3-one) is the major defence chemical protecting seedlings and young plant parts against herbivores and other pests. The two isoenzymes hydrolyse DIMBOAGlc with similar kinetics but differ from each other and their sorghum homologues with respect to specificity towards other substrates. To gain insights into the mechanism of substrate (i.

The valine-to-threonine 75 substitution in human immunodeficiency virus type 1 reverse transcriptase and its relation with stavudine resistance.

The amino acid change V75T in human immunodeficiency virus type 1 reverse transcriptase confers a low level of 2',3'-didehydro-2',3'-dideoxythymidine (stavudine, d4T) resistance in vivo and in vitro. Valine 75 is located at the basis of the fingers subdomain of reverse transcriptase between the template contact point and the nucleotide-binding pocket. V75T reverse transcriptase discriminates 3.

Crystal structure of aphrodisin, a sex pheromone from female hamster.

We have solved the crystal structure of aphrodisin, a pheromonal protein inducing a copulatory behaviour in male hamster, using MAD methods with selenium, at 1.63 A resolution. The monomeric protein belongs to the lipocalin family, and possesses a disulfide bridge in a loop between strands 2 and 3.

Stability of water bells generated by jet impacts on a disk.

Water bells appear when a cylindrical liquid jet impacts normally onto a disk of similar diameter. First observed and described experimentally by F. Savart, their stationary shape was analytically obtained by J.

Complementary cardioprotective effects of flavonoid metabolites and terpenoid constituents of Ginkgo biloba extract (EGb 761) during ischemia and reperfusion.

Hemodynamic and electron spin resonance (ESR) analyses were performed on isolated ischemic and reperfused rat hearts to assess the cardioprotective and antioxidant effects of therapeutically relevant concentrations of Ginkgo biloba extract (EGb 761; 5, 50 or 200 microg/ml), its terpenoid constituents (ginkgolide A; 0.05 microg/ml and ginkgolide B; 0.05, 0.

Visualization of the space-time impulse response of the subcritical wake of a cylinder.

The well-known Benard-von Karman cylinder wake is one of the most challenging phenomena of fluid mechanics. As the Reynolds number of the flow around a cylinder passes through a critical value, alternating vortex shedding appears via a Hopf bifurcation. Theoretical studies of the wake have described the appearance of this self-sustained oscillation as the result of a convective to absolute transition resulting in the formation of a global mode.

Use of diethyl(2-methylpyrrolidin-2-yl)phosphonate as a highly sensitive extra- and intracellular 31P NMR pH indicator in isolated organs. Direct NMR evidence of acidic compartments in the ischemic and reperfused rat liver.

The novel phosphorylated pyrrolidine diethyl(2-methylpyrrolidin-2-yl)phosphonate (DEPMPH) was evaluated as a (31)P NMR probe of the pH changes associated with ischemia/reperfusion of rat isolated hearts and livers. In vitro titration curves indicated that DEPMPH exhibited a 4-fold larger amplitude of chemical shift variation than inorganic phosphate yielding an enhanced NMR sensitivity in the pH range of 5.0-7.

2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide: evaluation of the spin trapping properties.

The 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-l-oxide (EMPO), an easily prepared pyrroline-N-oxide has been tested as a free radical scavenger. Spin adducts of superoxide, hydroxyl radical, and other free radicals were characterized in phosphate buffer at pH 7.0 and 5.

New perspectives on the cardioprotective phosphonate effect of the spin trap 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide: an hemodynamic and 31P NMR study in rat hearts.

The spin trap 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DEPMPO) is an improved ESR probe to assess superoxide (O2*-) formation in the postischemic heart. We recently found that DEPMPO pretreatment improves recovery of cardiac function with the concomitant inhibition of postischemic O2*- production. By perfusing diethyl methylphosphonate MeP(O)(OEt)2 to ischemic-reperfused isolated rat hearts, we provide hemodynamic evidence that this preservation, which exerts during ischemia, is in fact specific to the phosphonate group.

Protein kinases C-gamma and -delta are involved in insulin-like growth factor I-induced migration of colonic epithelial cells.

Background & Aims: The mechanisms by which epithelial cells migrate during the repair of damaged colonic mucosa are poorly understood. This study investigated the insulin-like growth factor I (IGF-I) signaling pathway leading to HT29-D4 human colonic epithelial cell line migration.

Methods: IGF-stimulated cell migration was determined using a wound model in the presence or absence of kinase inhibitors.

Nitrone spin traps and their pyrrolidine analogs in myocardial reperfusion injury: hemodynamic and ESR implications--evidence for a cardioprotective phosphonate effect for 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide in rat hearts.

Formation of free radicals during reperfusion of the isolated ischemic heart has often been demonstrated by detecting hydroxyl radical spin adducts of the nitrone 5,5-dimethyl-1-pyrroline N-oxide (DMPO) in coronary effluents. However, questions still remain regarding (a) whether the reported cardiovascular effects of nitrone perfusion may affect the formation of spin adducts, and (b) the primary generation of superoxide (O2.-), because of the short persistency of O2.

Sleep disturbances in man during different compression profiles up to 62 bars in helium-oxygen mixture.

Studies of sleep organization of 8 subjects were performed during 4 dives between 500 and 610 msw (51 and 62 bar) in a helium-oxygen mixture. The results of the 156 sleep records showed that sleep was disrupted from 30 bar: awake periods and stages I and II increased, stages III and IV and REM periods decreased. These disturbances, which were more intense with fast compression and recovered during decompression, can be considered as further symptoms of the high pressure nervous syndrome (HPNS).