Crystallization and preliminary X-ray crystallographic studies of benzamidine-inhibited trypsin from the North Atlantic salmon (Salmo salar)

Crystals of benzamidine-inhibited trypsin from the North Atlantic salmon (Salmo salar) have been grown from ammonium sulphate solution at pH 5.0. Two crystal forms suitable for X-ray structure analysis, obtained from a hanging-drop experiment, have been characterized. Both belong to space-group P22(1)2(1) with cell dimensions a = 39.2 A, b = 62.4 A, c = 84.6 A and a = 31.4 A, b = 74.8 A, c = 83.5 A, for forms I and II, respectively. Intensity data to 1.82 A have been collected for crystal form I on a CAD4 diffractometer, and initial phases have been obtained by molecular replacement methods. The conventional R-factor after two rounds of model building and subsequent refinement is 0.25 for data between 6.0 and 2.0 A. So far no water molecules have been included in the model.     

Carboxylic ionophore (lasalocid A and A23187) mediated lanthanide ion transport across phospholipid vesicles

The transport kinetics of three lanthanide ions (viz., Pr3+, Nd3+, and Eu3+) across dimyristoylphosphatidylcholine and dipalmitoylphosphatidylcholine unilamellar vesicles mediated by the two carboxylic ionophores lasalocid A and A23187 have been studied by proton nuclear magnetic resonance spectroscopy. Time-dependent changes in the chemical shifts of head group choline signals have been measured to calculate apparent rate constants of transport. These experiments have been done at different ionophore concentrations to determine the stoichiometry of the transporting species. The rates of transport have been found to be faster in the absence of intravesicular La3+ compared to those observed in its presence. The stoichiometry of the transporting species has been found to be 2:1 (ionophore:cation) for both lasalocid A and A23187 in dimyristoylphosphatidylcholine vesicles. However, stoichiometries of greater than 2 have been obtained for lasalocid A mediated lanthanide ion transport across dipalmitoylphosphatidylcholine vesicles. Possible reasons for the observations of such noninteger stoichiometries are discussed. Our results also indicated that A23187 is a more efficient carrier ionophore than lasalocid A.     

Proton nuclear magnetic resonance characterization of phospholipase A2 from Laticauda semifasciata

The molecular properties of phospholipases (PLases) A2 I and A2 III from a sea snake, Laticauda semifasciata, have been characterized by gel-filtration, as well as proton NMR, CD, UV absorption, and fluorescence spectroscopic methods. PLase A2 I exists as a monomer in aqueous solution in the presence or in the absence of Ca2+. The dissociation constants of the Ca2+-enzyme complexes have been determined for the two enzymes. The 270-mHz proton NMR spectra of PLases A2 I and A2 III have been measured, and the aromatic proton resonances of His-21 and His-48 in the active site have been assigned. By analyzing the pH dependence of the chemical shifts of the histidine proton resonances, pKa values have been determined for His-21 and His-48 with and without Ca2+. The conformational transitions have been found to take place at low pH or at high temperature (at approximately 65 degrees C). Fluorescence change of PLase A2 I upon addition of substrate analogs suggests that Trp-70 in PLase A2 I is involved in the binding to micellar substrates. The lack of Trp-70 in PLase A2 III is probably related to the low enzymatic activity as compared with that of PLase A2 I.     

Crystallization and preliminary X-ray diffraction analysis of oucleoside diphosphate kinase from Myxococcus xanthus.

Nucleoside diphosphate (NDP) kinase catalyzes the transfer of the gamma-phosphate from a nucleoside triphosphate to a nucleoside diphosphate. Human and rodent forms of this enzyme have been shown to be suppressors of metastasis. Crystals that diffract X-rays to high resolution have been obtained for the recombinant Myxococcus xanthus NDP kinase expressed in and purified from Escherichia coli. Two crystal forms have been obtained. Both forms are orthorhombic, space group I222 (or I2(1)2(1)2(1)) with a = 267.1 A, b = 74.0 A and c = 75.1 A for form I and a = 53.5 A, b = 74.0 A and c = 75.1 A for form II. Form I appears to have five molecules in the asymmetric unit approximately related to each other by a translation of 0.2 along the a axis. Diffraction data have been recorded to 1.9 A for form I and to 2.2 A for form II.     

Enkephalinases

Enkephalins can be degraded by a variety of peptidases. We have characterized several membrane-associated brain peptidases in an effort to determine which if any are concerned with the physiological inactivation of synaptically released enkephalin. We have distinguished two carboxyl-directed dipeptidylpeptidases, designated enkephalinase A1 and A2, that give rise to the Tyr-Gly-Gly fragment. Both enzymes are physically separable from angiotensin converting enzyme. Regional variations in enkephalinase A1 activity and opiate receptors are similar. A novel amino-terminal-directed dipeptidylpeptidase, enkephalinase B, which generates Tyr-Gly, has been identified. All of these enzymes as well as aminopeptidase have been solubilized from brain membranes by detergent treatment and have been mutually resolved by DEAE column chromatography. Enkephalinase A1 has been purified 1500-fold, to apparent homogeneity.     

The gene map of the pig (Sus scrofa domestica L.): a review.

A review of the present status of the porcine gene map is given with references. A total of 84 loci have now been studied, and genes have been assigned to 17 chromosomes. Among them, six chromosomes are defined by only one marker. No loci have been attributed yet to three chromosomes.     

Studies on the Constituents of Aristolochia mollissima Hance

Ten constituents have been isolated from the ethanolie extract of the stems and leaves of Aristolochia mollissima Hanee. Based on speetrai analysis and the determination of physieo-ehemieal constants they have been identified as: (A1) aristoloehie acid A, (A2) vanillie acid, (A3) aristoloehie acid D, (B1) pahnitone, (B2) n-triacontanol, (B3) β-sitosterol, (B1) aristololaetam, (B11)6-methoxy aristololaetam, (B7) β- sitosterol D-glueoside, (B8) stearic acid. A1 and B1 have been found to have an inhibition action of implantation in mice.     

具有中等毒性的马氏钳蝎神经毒素的纯化和初步晶体学研究

运用柱层析技术对产自淅川和常德的马氏钳蝎毒素进行分离纯化,得到８种哺乳动物神经毒素。运用制备型等电聚焦电泳技术,对常德样品中具有中等毒性的蝎神经毒素（ＢｍＫ５）进一步纯化,获得了高纯度样品。两个产地的蝎毒素ＢｍＫ５均已经成功地获得了大晶体。空间群均为Ｐ２１２１２１,晶胞参数分别为：ａ＝３８．４６埃,ｂ＝３７．２８埃,ｃ＝３６．９７埃（淅川）;ａ＝３８．４４埃,ｂ＝３７．５５埃,ｃ＝３６．８３埃（常德）。对两个产地的晶体分别收集了２．１埃（淅川）和１．６２埃（常德）分辨率的衍射数据。     

Initiating a crystallographic study of a class II fructose-1,6-bisphosphate aldolase.

We have reproducibly crystallized the metal-dependent Class II fructose-1,6-bisphosphate aldolase from Escherichia coli. Crystals in the shape of truncated hexagonal bipyramids have unit cell dimensions of a = b = 78.4 A, c = 290.6 A and are suitable for a detailed structural analysis. The space group has been identified as P6(1)22 or enantiomorph. Data sets to approximately 2.9 A resolution have been recorded using both the Rigaku R-AXIS IIc image plate area detector coupled to a copper target rotating anode X-ray source and using the MAR image plate systems with synchrotron radiation at the EMBL outstation DESY in Hamburg, and at S.R.S. Daresbury. Diffraction beyond 2.5 A has been observed when large freshly grown crystals are used with the synchrotron beam. A data set to this resolution has been collected. Several putative heavy-atom derivative data sets have also been measured using synchrotron radiation facilities and analysis of these data sets is in progress.     

Structural analysis of 21-hydroxypregn-4-ene-3,20-dione (deoxycorticosterone) derivative compounds. Part I: Synthesis and circular dichroism identification

Deoxycorticosterone (DOC) derivative compounds (DOC, DOC 21-acetate, and 7-mercaptopropionic DOC) have been prepared and purified by high pressure liquid chromatography. Synthesis products have been identified, and three chromophores have been displayed by their n----II and II----II dichroic transitions. A normal half-chair conformation is favored in ring A.     

The Comparison of the Chemical Composition from Natural Atractylodes macrocephala Koidz and Its Tissue Culture

The essential oils of the rhizomes from natural A. macrocephala and its tissus culture have been extracted. The chemical components of these essential oils have been determined and compared by TLC and GC-MSD. Their chemical components are identical and thirteen components have been identified as β-humulene, ρ-elemol, α-humulene, α-curcumene, 3β-ace-toxyatractylon and isobutenolide, A, selina-4(14)-7(ll) diene-8-one, atractylon, anhydrobutenolide, palmitic acid, butenolid A, eudesmol and hydroxybutenolide. Six compounds are first reported containing in A. macrocephala.     

Vitamin A,Pregnancy, and Oral Contraceptives

It has been shown that women receiving oral contraceptives have increased levels of serum vitamin A. High vitamin A levels may constitute a teratogenic hazard and it has been suggested that women who conceive soon after discontinuing oral contraceptive therapy may be especially at risk to this hazard.We have confirmed a significant increase in vitamin A levels in women taking oral contraceptives. During early pregnancy there is no significant difference in vitamin A levels between women who have recently been taking oral contraceptives and those who have not. We have been unable to show that either taking oral contraceptives shortly before pregnancy or a high vitamin A level during the first trimester of pregnancy, comparable to that of a woman taking oral contraceptives, has any detrimental effect on the outcome of pregnancy. It seems unlikely that women who conceive soon after discontinuing oral contraception run any teratogenic risk from increased vitamin A levels.     

Variability of the mitochondrial gene for cytochrome oxidase I within the Adalia bipunctata species and within species of ladybird beetles (Coleoptera: Coccinellidae)

Intergeneric, interspecific, and intraspecific genetic variation of the 310-bp 3'-end region of the mitochondrial gene of cytochrome oxidase I (COI) has been assessed in ladybirds (Coleoptera: Coccinnellidae). The phylogenetic distances between eight species of ladybirds have been determined. Mitochondrial DNA (mtDNA) nucleotide sequences have been compared in Adalia bipunctata L. differing in the elytron and pronotum colors that have been sampled from several geographically remote populations. The taxonomic statuses of two morphs from the genus Adalia, A. bipunctata bipunctata and A. bipunctata fasciatopunctata, have been identified.     

枯草杆菌蛋白酶E的结晶及初步衍射研究

对来源于枯草芽孢杆菌的枯草杆菌蛋白酶E进行了初步晶体学研究。应用悬滴汽相扩散法生长出了该酶的单晶体,其空间群为P2_12_12_1,晶胞边长a=74.35A,b=80.98A,c=88.59A。已用面探测器衍射仪收集了一套中等分辨率的X射线衍射数据。     

Kink dynamics in inhomogeneous DNA

A mathematical model for studies of peculiar features of the dynamics of local conformational distortions (kinks) has been constructed. General formulas determining the dependence of the main dynamic characteristics of kinks: size, energy, density of energy, and velocity on the composition of inhomogeneous DNA have been obtained. Quantitative estimations of the characteristics have been made for kinks activated in inhomogeneous polynucleotide chains with sequences analogous to promoter sequences A1, A2, and A3 of bacteriophage T7 genome.     

Synthesis of 7'-(3-hydroxypropyl)fortimicin A and 6'-epifortimicin A

1,10-Di-0-acetyl-2,3,4,6,7,8,9-heptadeoxy-2,6-bis(2, 4-dinitrophenylamino)-L-lyxo-decopyranose (7) and -D-ribo-decopyranose (8) have been prepared from methyl 2-acetamido-2,3,4,6-tetradeoxy-6-nitro-alpha-D-erythro-hexopyranoside via a nitro aldol reaction with 4-[(tetrahydropyranyl)oxy]butanal in the presence of cesium fluoride, and their configurations at C-6 have been established by conversion of the precursor of 8, namely, methyl 2,6-diacetamido-10-O-acetyl-2,3,4,6,7,8,9-heptadeoxy-alpha-D - ribo-decopyranoside, into the known methyl 2,6-diacetamido-2,3,4,6,7,8,9,10-octadeoxy-alpha-D-ribo-d ecopyranoside. The title fortimicin A derivatives, 7'-(3-hydroxypropyl)fortimicin A and 6'-epifortimicin A, have been synthesized by condensation of compound 7 and 8, respectively, with 2,5-di-O-benzoyl-1,4-bis[N-(methoxycarbonyl)]fortamine B, followed by deprotection and introduction of a glycyl group. Their antimicrobial activities have been found to be weak compared to that of fortimicin A.     

Type A behaviour pattern: a concept revisited.

It is generally accepted that the type A behaviour pattern is a risk factor in the development of coronary artery disease (CAD). Type A people have been characterized as hard-driving, competitive, aggressive and hurried. A number of investigators have attempted to correlate these facets of type A behaviour with increased risks of CAD. However, there have been conflicting results, primarily owing to differences in methods and CAD outcomes and inconsistencies associated with measuring the type A behaviour pattern. As a result, researchers have begun to focus on subcomponents of the type A behaviour pattern, particularly hostility and anger, that appear to be more reliable predictors of CAD outcome. A reconceptualization of the type A behaviour pattern is required.     

Nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in a dielectric medium

A nonlinear quantum theory of stimulated Cherenkov radiation of transverse electromagnetic waves from a low-density relativistic electron beam in an isotropic dielectric medium is presented. A quantum model based on the Klein-Gordon equation is used. The growth rates of beam instabilities caused by the effect of stimulated Cherenkov radiation have been determined in the linear approximation. Mechanisms of the nonlinear saturation of relativistic quantum Cherenkov beam instabilities have been analyzed and the corresponding analytical solutions have been obtained.