Identification of binding sites of prazosin, tamsulosin and KMD-3213 with alpha(1)-adrenergic receptor subtypes by molecular modeling.

This investigation was performed to assess the importance of interaction in the bindings of selective and nonselective alpha(1)-antagonists to alpha(1)-adrenergic receptor (alpha(1)-AR) subtypes using molecular modeling. The alpha(1)-antagonists used in this study were prazosin, tamsulosin and KMD-3213. Molecular modeling was performed on Octane 2 workstation (Silicon Graphics) using Discover/Insight II software (Molecular Simulations Inc.

A novel tachykinin-related peptide receptor. Sequence, genomic organization, and functional analysis.

Structurally tachykinin-related peptides have been isolated from various invertebrate species and shown to exhibit their biological activities through a G-protein-coupled receptor (GPCR) for a tachykinin-related peptide. In this paper, we report the identification of a novel tachykinin-related peptide receptor, the urechistachykinin receptor (UTKR) from the echiuroid worm, Urechis unitinctus. The deduced UTKR precursor includes seven transmembrane domains and typical sites for mammalian tachykinin receptors and invertebrate tachykinin-related peptide receptors.

Potent antagonistic action of synthetic analogues of APGWGNamide, an antagonist of molluscan neuropeptide APGWamide.

Fifty-five kinds of analogues of APGWGNamide (Ala-Pro-Gly-Trp-Gly-Asn-NH2), which is an antagonist of molluscan neuropeptide APGWamide, were synthesized and their antagonistic activities were examined on two molluscan smooth muscles. Among all the analogues tested, on spontaneous contraction of the crop of the land snail, Euhadra congenita, APGWG(L-biphenylalanine, Bip)amide showed the most potent antagonistic activity and its potency was 50-100 times higher than that of APGWGNamide. Likewise, on phasic contraction of the anterior byssus retractor muscle (ABRM) of the sea mussel, Mytilus edulis, the effect of APGWG(D-homophenylalanine, dHfe) was the most potent and showed 5-10 times stronger activity than that of APGWGNamide.

Novel proteinaceous toxins from the nematocyst venom of the Okinawan sea anemone Phyllodiscus semoni Kwietniewski.

The Okinawan sea anemone Phyllodiscus semoni is known to cause cases of severe stinging. We isolated P. semoni toxins 60A and 60B (PsTX-60A and PsTX-60B; ca.

Location of functional groups in mycobacterial meromycolate chains; the recognition of new structural principles in mycolic acids.

Mycobacterial alpha-, methoxy- and keto-mycolic acid methyl esters were separated by argentation chromatography into mycolates with no double bond, with one trans double bond or with one cis double bond. Meromycolic acids were prepared from each methyl mycolate fraction by pyrolysis, followed by silver oxide oxidation, and analysed by high-energy collision-induced dissociation/fast atom bombardment MS to reveal the exact locations of the functional groups within the meromycolate chain. The locations of cis and trans double bonds, cis and trans cyclopropane rings, methoxy and keto groups, and methyl branches within the meromycolate chain were determined from their characteristic fragment ion profiles, and the structures of the meromycolic acids, including those with three functional groups extracted from Mycobacterium tuberculosis H37Ra, Mycobacterium bovis BCG and Mycobacterium microti, were established.

Purification, structure-function analysis, and molecular characterization of novel linear peptides from scorpion Opisthacanthus madagascariensis.

In the previous report [Biochem. Biophys. Res.

Sequencing wasp venom peptides by endopeptidase digestion and nested collision-induced dissociation/post-source decay methods.

A method incorporating nested collision-induced dissociation/post-source decay (CID/PSD) combined with endopeptidase digestion is described as an approach to determine the sequence of N-terminally modified peptides. The information from immonium and related ions observed in the CID/PSD spectrum was used for the selection of a suitable endopeptidase for the digestion of peptides. Rapid and reliable assignment of peptide sequence was performed by the comparison of CID/PSD spectra of both intact and endopeptidese-digested peptide fragments, since the assignments of the observed fragment ions to either N- or C-terminal ions can thus be carried out unambiguously.

Oxyopinins, large amphipathic peptides isolated from the venom of the wolf spider Oxyopes kitabensis with cytolytic properties and positive insecticidal cooperativity with spider neurotoxins.

Five amphipathic peptides with antimicrobial, hemolytic, and insecticidal activity were isolated from the crude venom of the wolf spider Oxyopes kitabensis. The peptides, named oxyopinins, are the largest linear cationic amphipathic peptides from the venom of a spider that have been chemically characterized at present. According to their primary structure Oxyopinin 1 is composed of 48 amino acid residues showing extended sequence similarity to the ant insecticidal peptide ponericinL2 and to the frog antimicrobial peptide dermaseptin.

Structure-activity relationships for mini atrial natriuretic peptide by proline-scanning mutagenesis and shortening of peptide backbone.

MiniANP is a synthetic pentadecapeptide analogue of atrial natriuretic polypeptide (ANP). We have used the proline-scanning mutagenesis and the analogue peptides with shorter backbones to characterize the turn-like conformation at residue 6-9 and an extended structure of Gly5-Gly6 as the receptor-bound structure of miniANP. A docking study of miniANP at the binding site of the type A natriuretic peptide receptor (NPR-A) supported the deduced conformation in the receptor-bound structure.

Isolation and characterization of a GnRH-like peptide from Octopus vulgaris.

Gonadotropin-releasing hormone (GnRH) is the key peptide in the hypothalamo-hypophysial-gonadal axis, the core of regulation of reproduction in vertebrates. In this study, an octopus peptide with structural features similar to vertebrate GnRHs was isolated from brains of Octopus vulgaris. This peptide showed luteinizing hormone-releasing activity in quail anterior pituitary cells.

A novel protein toxin from the deadly box jellyfish (Sea Wasp, Habu-kurage) Chiropsalmus quadrigatus.

The deadly box jellyfish (Sea Wasp, Habu-kurage in Japanese) Chiropsalmus quadrigatus Haeckel (Cubozoa) is distributed widely in the tropical Pacific region. In Japan, three fatal cases due to stings from this species have been reported officially. We successfully isolated C.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and high-performance liquid chromatography study of quantitative and qualitative variation in tarantula spider venoms.

Animal venoms are important sources of novel pharmacological tools, useful in biochemical characterization of their receptors. Venom quality control, batch-to-batch homogeneity and high reproducibility of venom fractionation and toxin purification are crucial issues for biochemical and pharmacological studies. To address these issues, a study of the variability of tarantula spider venom samples was undertaken.

Designing analogues of mini atrial natriuretic peptide based on structural analysis by NMR and restrained molecular dynamics.

Analogues of mini atrial natriuretic peptide (miniANP) that provide conformational properties related to biological activity were designed on the basis of the structure revealed by NMR and restrained molecular dynamics (rMD) simulation, and an analogue with a high level of biological activity was successfully obtained. MiniANP is a cyclic pentadecapeptide analogue of atrial natriuretic polypeptide (ANP). The conformation of miniANP analyzed by NMR and rMD simulation indicated that positive phi angles are preferred for Gly(5) and Gly(6), which is typical for D-amino acids.

Cloning and expression of a cDNA for a putative G protein-coupled receptor from the hepatopancreas of the crayfish, Procambarus clarkii.

The authors cloned a novel cDNA encoding a putative G protein-coupled receptor (GPCR) from the hepatopancreas of the crayfish, Procambarus clarkii, using a screening approach with synthetic oligonucleotides. The oligonucleotides were designed homologous to the transmembrane spanning domain III of previously cloned receptors from various living organisms. Sequence analysis revealed that one of the positive clones contained a cDNA insertion of 3489 bp representing the mRNA coding for a part of a putative GPCR (termed HP1R).

[New orally active penem antibiotic: Farom].

An orally active penem antibiotic, Farom (generic name: faropenem), was designed by the conformational analysis of active and inactive penem derivatives. Faropenem showed potent activity against a wide variety of bacteria including extended-spectrum beta-lactamase (ESBL)-producing ones. The mechanism of the stability against ESBL was elucidated by modeling the Michaelis complex of faropenem and Toho-1, an ESBL.

Colopsinol A, a Novel Polyhydroxyl Metabolite from Marine Dinoflagellate Amphidinium sp.

Colopsinol A (1), a novel polyhydroxyl compound, has been isolated from the cultured marine dinoflagellate Amphidinium sp., from which a number of cytotoxic macrolides, amphidinolides, have been obtained to date, and the gross structure of 1 was elucidated on the basis of extensive spectroscopic analyses including recent 2D NMR techniques of CH(2)-selected editing HSQC as well as FABMS/MS experiments and chemical means. Colopsinol A (1), C(71)H(119)O(25)SNa, is the first member of a new class of polyketide natural products possessing a gentiobioside moiety and a sulfate ester.

Characterization of unique amphipathic antimicrobial peptides from venom of the scorpion Pandinus imperator.

Two novel antimicrobial peptides have been identified and characterized from venom of the African scorpion Pandinus imperator. The peptides, designated pandinin 1 and 2, are alpha-helical polycationic peptides, with pandinin 1 belonging to the group of antibacterial peptides previously described from scorpions, frogs and insects, and pandinin 2 to the group of short magainin-type helical peptides from frogs. Both peptides demonstrated high antimicrobial activity against a range of Gram-positive bacteria (2.

IsCT, a novel cytotoxic linear peptide from scorpion Opisthacanthus madagascariensis.

A novel cytotoxic linear peptide, IsCT, was characterized from scorpion Opisthacanthus madagascariensis. It is a linear peptide with a molecular weight of 1501.9 Da composed of 13 amino acid residues without cysteines.

Novel peptides from assassin bugs (Hemiptera: Reduviidae): isolation, chemical and biological characterization.

Three novel peptides were isolated from the venomous saliva of predatory reduviids. They were identified by mass spectrometry and HPLC analysis and consist of 34-36 amino acid residues. They are relatively homologous to the calcium channel blockers omega-conotoxins from marine cone snails and belong to the four-loop Cys scaffold structural class.

Reaction of Lys-Tyr-Lys triad mimics with benzylpenicillin: insight into the role of Tyr150 in class C beta-lactamase.

Small and simple molecules mimicking a Lys-Tyr-Lys triad and some 'mutant' derivatives were designed and synthesized. These-compounds react with benzylpenicillin in water (75mM phosphate buffer, pH 7), apparently through general base assistance by the phenolic moiety. Class C beta-lactamase has a Lys-Tyr-Lys triad in its active site, and our finding gives some insight into the role of this triad in the enzymatic beta-lactam hydrolysis mechanism.

Characterization of a cDNA encoding a novel avian hypothalamic neuropeptide exerting an inhibitory effect on gonadotropin release.

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH(2) sequence, SIKPSAYLPLRF-NH(2) (RFamide peptide), from the quail brain. This quail RFamide peptide was shown to decrease gonadotropin release from the cultured anterior pituitary and to be located at least in the quail hypothalamo-hypophysial system. We therefore designated this RFamide peptide gonadotropin inhibitory hormone (GnIH).

Identification of multiple urechistachykinin peptides, gene expression, pharmacological activity, and detection using mass spectrometric analyses.

Urechistachykinin I and II (Uru-TK I and II) are invertebrate tachykinin-related peptides (TRPs), which have been isolated from echiuroid worms. The cDNA sequence encoding the Uru-TK I and II revealed that the precursor also encoded five TRP-like peptides. Here, we report the characterization of these Uru-TK-like peptides named as Uru-TK III-VII.

New malyngamides from the Hawaiian cyanobacterium Lyngbya majuscula.

Isomalyngamides A and B (1, 2) were isolated and characterized from a collection of the cyanobacterium Lyngbya majuscula from Hawaiian waters. These compounds represent a new type of malyngamide, similar to malyngamides Q and R, in which the conformation of the chloromethylene group is opposite from the majority of previously reported malyngamides. The geometry of the chloromethylene moiety was elucidated from the long-range coupling constants ((3)J(C)(-)(H)) obtained from editing-HETLOC and phase-sensitive HMBC experiments.

Syntheses of optically pure beta-hydroxyaspartate derivatives as glutamate transporter blockers.

DL-threo-beta-benzyloxyaspartate (DL-TBOA) is a non-transportable blocker of the glutamate transporters that serves as an indispensable tool for the investigation of the physiological roles of the transporters. To examine the precise interaction between a blocker and the transporters, we synthesized the optically pure isomers (L- and D-TBOA) and its erythro-isomers. L-TBOA is the most potent blocker for the human excitatory amino acid transporters (EAAT1-3), while D-TBOA revealed a difference in the pharmacophores between EAAT1 and EAAT3.

Sequence and electrophysiological characterization of two insect-selective excitatory toxins from the venom of the Chinese scorpion Buthus martensi.

The two insecticidal peptides Bm32-VI and Bm33-I, isolated from the venom of the Chinese scorpion Buthus martensi induce paralytical symptoms typical of insect contractive toxins. They show, respectively, 74% and 77% homology with AaIT from Androctonus australis, comparable insecticidal activity and no vertebrate toxicity. Under voltage-clamp conditions, both toxins induced (1) an increased fast Na(+) current, (2) a shift in voltage dependence of Na(+) current activation, (3) the occurrence of a delayed current, and (4) a slow development of a holding current.