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1.
Hiroyoshi Omokawa Izumi Kobayashi Makoto Konnai 《Bioscience, biotechnology, and biochemistry》2013,77(10):2723-2729
The influence of substituents on the activities of a series of N2-α-substituted benzyl-N4-alkyl-2,4-diamino-6-chloro-s-triazines as inhibitors of photosystem II (PSII) was examined, and the phytotoxic differences between them and atrazine, as to the photosynthesis in leaf disks, mesophyll cells, intact chloroplasts and broken chloroplasts of spinach, and as to seedling-growth, were discussed. The inhibitory activity of the N2-α,α-dimethylbenzyl-N4-ethyl derivative (6), which was comparable on that of atrazine, was lower than those of the N2-α-alkylbenzyl analogues (1 ~5). The N4-?-alkyl-N2-α- methylbenzyl derivatives, in spite of the carbon length of the alkyl group, exhibited more potent activity than atrazine, but an a α β substitution of the N4-n-alkyl group caused a decrease in the activity with a few exceptions. These data may imply that the space of the binding site on PSII surrounding both the N2 and N4 amino groups is relatively large. The binding between the receptor site and the N4 amino group, however, is easily influenced by a slight structural change in an inhibitor. The herbicidal compounds, N2-α-methylbenzyl-A^4-ethyl (1), A^2-α,α-dimethylbenzyl-N4-1-methylpropyl (30) and N2-α-methylbenzyl-N4,N4-diethyl (42) derivatives, exhibited potent inhibitory activity in the seedling growth test under dark/light conditions, whereas atrazine was very poor. The inhibitory activity of compound (1) toward photosynthesis was poor with leaf disks, compared to atrazine, whereas, the order of their activities was the reverse for plant preparations such as abaxial epidermis peeled leaf disks, mesophyll cells, intact chloroplasts and broken chloroplasts. It was indicated that a change in the phytotoxic symptom in the whole plant assay would be correlated to the permeability of the compound through the plant membrane(s). 相似文献
2.
The presence of a novel coaggregation receptor polysaccharide (RPS) on the dental plaque isolate Streptococcus cristatus LS4 was suggested by this strain’s antigenic and coaggregation properties. Examination of RPS isolated from strain LS4 by a combination of 2-dimensional and pseudo 3-dimensional single quantum heteronuclear NMR methods that included detection of 13C chemical shifts at high resolution revealed the following repeat unit structure:→6)-β-d-Galf-(1→6)-β-d-GalpNAc-(1→3)-α-d-Galp-(1→P→6)-α-d-Galp-(1→3)-β-L-Rhap-(1→4)-β-d-Glcp-(1→.The identification of this polysaccharide as RPS3Gn, a new structural type, was established by the α-d-Galp-containing epitope of RPS serotype 3 and Gn recognition motif (i.e., β-d-GalpNAc (1→3)-α-d-Galp) for coaggregation with other bacteria. 相似文献
3.
(±)-(2Z,4E)-α-Ionylideneacetic acid (2) was enantioselectively oxidized to (?)-(l′S)-(2Z,4E)-4′-hydroxy-α-ionylideneacetic acid (3), (+)-(1′R)-(2Z,4E)-4′-oxo-α-ionylideneacetic acid (4) and (+)-abscisic acid (ABA) (1) by Cercospora cruenta IFO 6164, which can produce (+)-ABA and (+)-4′-oxo-α-acid 4. This metabolism was confirmed by the incorporation of radioactivity from (±)-(2-14C)-(2Z,4E)-α-acid 2 into three metabolites. (?)-4′-Hydroxy-α-acid 3 was a diastereoisomeric mixture consisting of major 1′,4′-trance-4′-hydroxy-α-acid 3a and minor 1′,4′-cis-4′-hydroxy-α-acid 3b. These structures, 3a and 3b, were confirmed by 13C-NMR and 1H-NMR analysis. Also, the enantioselectivity of the microbial oxidation was reexamined by using optically pure α-acid (+)-2 and (?)-2, as the substrates. 相似文献
4.
《Bioscience, biotechnology, and biochemistry》2013,77(6):1496-1498
We isolated and identified the glyceraldehyde-derived advanced glycation product (AGE) formed from glyceraldehyde and N α-acetylarginine. A major product was identified as N α-acetyl-N δ-(5-methyl-imidazolin-4-one-2-yl)-ornithine. The compound has been reported as methylglyoxal-derived AGE, MG-H1. This study suggests that MG-H1 is formed through both glyceraldehyde-related and methylglyoxal-related pathways. There is a possibility that MG-H1 becomes an index of injury to glyceraldehyde and methylglyoxal-related enzymes. 相似文献
5.
Andrei V. Perepelov Nina A. Kocharova Yuriy A. Knirel Per-Erik Jansson Andrej Weintraub 《Carbohydrate research》2011,346(3):1951
The O-polysaccharide of Vibriocholerae O43 was studied using chemical analyses, triflic acid solvolysis and 2D NMR spectroscopy, including 1H/1H COSY, TOCSY, NOESY and 1H/13C gradient-selected HSQC experiments. The following structure of the tetrasaccharide repeating unit of the polysaccharide was established:→3)-β-d-Quip4NAcyl-(1→3)-α-d-GalpNAcA-(1→4)-α-d-GalpNAc-(1→3)-α-d-QuipNAc-(1→where d-QuiNAc stands for 2-acetamido-2,6-dideoxy-d-glucose, d-Qui4NAcyl for 4-(N-acetyl-l-allothreonyl)amino-4,6-dideoxy-d-glucose and d-GalNAcA for 2-acetamido-2-deoxy-d-galacturonic acid. 相似文献
6.
《Journal of receptor and signal transduction research》2013,33(1-6):315-329
AbstractExcised dorsal skin of Anolis carolinensis was exposed to high intensity UV-irradiation in the presence of different photoreactive α-MSH derivatives. The resulting covalent binding of the hormone to its receptor induced irreversible pigment dispersion. The duration of the longlasting response depended on the type and length of irradiation; it was maximal after two 5 min irradiation phases with a light intensity of ~180 mW/cm2 and a spectrum from 310 to 550 nm, fresh hormone being added after the first phase. [Nα-(4-Azidophenyl-acetyl-serine1]-α-MSH (I), [2′-(2-nitro-4-azidophenylsulphenyl)-tryptophan9]-α-MSH (II) and [p-azidophenylalanine13]-α-MSH (III) all inserted into the receptor to about the same extent, as judged from the persistence of the longlasting signal. In contrast, [D-alanine1, p-azidophenylalanine2, norvaline4]-α-MSH (IV) and [Nα-(4-azidophenylacetyl)-serine1, leucine9]-α-MSH (V) gave much less insertion and [leucine9, p-azidophenylalanine13]-α-MSH (VI) hardly any insertion when applied in the same relative excess (5-fold the concentration inducing a maximal response). Covalent attachment of the cleavable photolabel [Nα-(4-azidophenyl)-1, 3′-dithio-propionyl-serine1]-α-MSH (VII) and subsequent washing of the skin in buffer containing 1% β-mercaptoethanol released the peptide from the receptor. Insertion of the C-terminal photolabel [p-azidophenylalanine13]-α-MSH was reduced by the weak antagonist H-Phe-Ala-Trp-Gly-Gly-Pro-Val-NH2. These experiments prove that hormone receptors can be covalently labelled in tissue with very limited light transparency. 相似文献
7.
Tiantian Sun Wei Zhang Chengli Zong Peng Wang Yingxia Li 《Journal of peptide science》2010,16(7):364-374
The first total synthesis of tasiamide B, an octapeptide bearing 4‐amino‐3‐hydroxy‐5‐phenylpentanoic acid unit isolated from the marine cyanobacteria Symploca sp. is described. A simple and efficient way was found to avoid the pyroglutamylation of Nα‐Me‐Gln and led to a reassignment of the Nα‐Me‐L ‐Phe of tasiamide B to be Nα‐Me‐D ‐Phe, which was also supported by 1D and 2D NMR. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
8.
Bogdan Doboszewski Piet A. M. Herdewijn 《Nucleosides, nucleotides & nucleic acids》2013,32(9):1495-1518
Abstract The synthesis of 1-[4-deoxy-4-C-hydroxymethyl-α-L-lyxopyranosyl]thymine has been accomplished by two synthetic routes both starting from methyl 2, 3-O-isopropylidene-β-D-ribopyranoside. The first route makes use of a ring opening, ring closure reaction sequence to increase the proportion of the desired L-isomers. The second route utilizes the soft nucleophilic character of malonyl anions and ozonolytic cleavage of enol ether to introduce the branched chain. The newly obtained pyranosyl nucleoside obtains a 4C1 conformation with an equatorially oriented thymine moiety. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(9):2418-2422
(RS)-β-Ionol and (RS)-2-methyl-4-octanol were resolved by using (S)-2-methoxy-2-(1-naphthyl)propanoic acid [(S)-MαNP acid]. The specific stereochemistry of each MαNP ester was elucidated by 2D NMR analyses, and shielding by the 1-naphthyl group was observed in both the 1H- and 13C-NMR spectra. Solvolysis of the individual (S)-MαNP esters gave four single-enantiomer alcohols. The normal-phase HPLC elution order of each MαNP ester is also discussed. 相似文献
10.
Analogs of Ac-[Nle4]-α-MSH4–11-NH2 and Ac-[Nle4, D -Phe7]-α-MSH4–11-NH2 were prepared with D -isomeric replacements at the His6, Arg8, and Trp9 residues. The requirement for an indole moiety at position 9 also was evaluated by replacement with L -leucine in both parent fragment analogs. D -isomeric replacements at positions 6 and 8 in either series were detrimental to biological potency in frog (Rana pipiens) and lizard skin (Anolis carolinensis) in vitro melanotropic assays. However, Ac-[Nle4, D -Trp9]-α-MSH4–11-NH2 and Ac-[Nle4, D -Phe7, D -Trp9]-α-MSH4–11-NH2 were equipotent and 10 × more potent than Ac-[Nle4]-α-MSH4–11-NH2, respectively, in the lizard skin bioassay, and 30 and 1900 times more potent in the frog skin bioassay. Ac-[Nle4, D -Phe7, D -Trp9]-α-MSH4–11-NH2 was 3 × more potent than α-MSH in the frog skin bioassay. Proton nmr studies in aqueous solution revealed a marked preservation of the backbone conformation of these linear analogs. Chemical-shift variations due to the through-space anisotropic influence of the core aromatic amino acid residues permitted evaluation of side-chain topology. The observed topology was consistent with nonhydrogen-bonded β-like structure (? = ?139°, ψ = +135° for L -amino acids; ? = +139°, ψ = ?135° for D -amino acids) as the predominant solution conformation. The biological and conformational data suggest that high melanotropic potency requires a close spatial arrangement of the His6, Phe7, and Arg8 side chains. 相似文献
11.
Tadasu Urashima Sachiko Murata Tadashi Nakamura 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1997,116(4):431-435
Acidic oligosaccharides were separated by dialysis, ion-exchange, preparative paper and gel chromatography from caprine colostrum. Four sialyl trisaccharides were characterized by 1H-NMR spectrometry as follows: α-N-acetylneuraminyl-(2,6)-β-d-galactopyranosyl-(1,4)-2-N-acetamido-2-deoxy-d-glucopyranose (Neu5Ac α 2-6Gal β 1-4GlcNAc), α-N-acetylneuraminyl-(2,3)-β-d-galactopyranosyl-(1,4)-d-glucopyranose (Neu5Ac α 2-3Gal β-1-4Glc), α-N-acetylneuraminyl-(2,6)-β-d-galactopyranosyl-(1,4)-d-glucopyranose (Neu5Ac α 2-6Gal β 1-4Glc) and α-N-glycolylneuraminyl-(2,6)-β-d-galactopyranosyl-(1,4)-d-glucopyranose (Neu5Gc α 2-6Gal β 1-4Glc). 相似文献
12.
Giovanni Valle Monica Pantano Fernando Formaggio Marco Crisma Claudio Toniolo Gilles Prcigoux Gerlind Sulzenbacher Wilhelmus H. J. Boesten Quirinus B. Broxterman Hans E. Schoemaker Johan Kamphuis 《Biopolymers》1993,33(10):1617-1625
The molecular and crystal structures of one derivative and three homopeptides (from the di-to the tetrapeptide level) of the chiral, Cα, α-disubstituted glycine Cα-methyl, Cα-benzylglycine [(αMe)Phe], have been determined by x-ray diffraction. The derivative is mClAc-D -(αMe)Phe-OH, and the peptides are pBrBz-[D -(αMe)Phe]2-NHMe, pBrBz-[D -(αMe)Phe]3-OH hemihydrate, and pBrBz-[D -(αMe)Phe]4-OtBu sesquihydrate. All (αMe)Phe residues prefer ?,ψ torsion angles in the helical region of the conformational map. The dipeptide methylamide and the tripeptide carboxylic acid adopt a β-turn conformation with a 1 ← 4 C?O…?H? N intramolecular H bond. The structure of the tripeptide carboxylic acid is further stabilized by a 1 ← 4 C?O…?H? O intramolecular H bond, forming an “oxy-analogue” of a β-turn. The tetrapeptide ester is folded in a regular (incipient) 310-helix. In general, the relationship between (αMe)Phe chirality and helix screw sense is opposite to that exhibited by protein amino acids. A comparison is made with the conclusions extracted from published work on homopeptides from other Cα-methylated α-amino acids. © 1993 John Wiley & Sons, Inc. 相似文献
13.
Abstract 2′-Deoxy-5′-0-(4,4′-dimethoxytrityl)-5-methyl-N 4-(1-pyrenylmethyl)-α-cytidine (5) was prepared by reaction of 1-pyrenylmethylamine with an appropriate protected 4-(l,2,4-triazolyl)-α-thymidine derivative 3 which was synthesized from 5-O-DMT protected α-thymidine 1. Aminolysis of 3 afforded 3′-O-acetyl-2′-deoxy-5′-O-(4,4′-dimethoxytrityl)-5-methyl-α-cytidine (8). Benzoylation of 8 and removal of acetyl afforded N 4-benzoyl-2-deoxy-5–0-(4,4′-dimethoxytrityl)-5-methyl-α-cytidine (10). The amidites of compounds 5and 10 were prepared and used in α-oligonucleotide synthesis. DNA three-way junction (TWJ) is stabilized when an α-ODN is used for targeting the dangling flanks of the stem in a DNA hairpin. Further stabilization of the TWJ is observed when 5 is inserted into the α-ODN at the junction region. 相似文献
14.
The structure of the O-antigen polysaccharide (PS) from Escherichia coli O175 has been elucidated. Component analysis together with 1H and 13C NMR spectroscopy experiments were used to determine the structure. Inter-residue correlations were determined by 1H,1H-NOESY, and 1H,13C-heteronuclear multiple-bond correlation experiments. The PS is composed of pentasaccharide repeating units with the following structure:→2)-α-d-Glcp-(1→4)-α-d-GlcpA-(1→3)-α-d-Manp-(1→2)-α-d-Manp-(1→3)-β-d-GalpNAc-(1→Cross-peaks of low intensity from an α-linked glucopyranosyl residue were present in the 1H,1H-TOCSY NMR spectra. The α-d-Glcp residue is suggested to originate from the terminal part of the polysaccharide and consequently the biological repeating unit has a 3-substituted N-acetyl-d-galactosamine residue at its reducing end. The repeating unit of the E. coli O175 O-antigen is similar to those from E. coli O22 and O83, both of which carry an α-d-Glcp-(1→4)-d-GlcpA structural element, thereby explaining the reported cross-reactivities between the strains. 相似文献
15.
《Bioscience, biotechnology, and biochemistry》2013,77(11):2406-2411
α-D-Mannosyl-maltotriose (Man-G3) were synthesized from methyl α-mannoside and maltotriose by the transfer action of α-mannosidase. (Man-G3)-βCD and (Man-G3)2-βCD were produced in about 20% and 4% yield, respectively when Aerobacter aerogenes pullulanase (160 units per 1 g of Man-G3) was incubated with the mixture of 1.6 M Man-G3 and 0.16 M βCD at 50°C for 4 days. The reaction products, (Man-G3)-βCD were separated to three peaks by HPLC analysis on a YMC-PACK A-323-3 column and (Man-G3)2-βCD were separated to several peaks by HPLC analysis on a Daisopak ODS column. The major product of (Man-G3)-βCDs was identified as 6-O-α-(63-O-α-D-mannosyl-maltotriosyl)-βCD by FAB-MS and NMR spectroscopies. The structures of (Man-G3)2-βCDs were analyzed by TOF-MS and NMR spectroscopies, and confirmed by comparison of elution profiles of their hydrolyzates by α-mannosidase and glucoamylase on a graphitized carbon column with those of the authentic di-glucosyl-βCDs. The structures of three main components of (Man-G3)2-βCDs were identified as 61,62-, 61,63- and 61,64-di-O-(63-O-α-D-mannosyl-maltotriosyl)-βCD. 相似文献
16.
《Bioscience, biotechnology, and biochemistry》2013,77(2):179-183
α-Linked galactooligosaccharides (α-GOS A from galactose, and α-GOS B from lactose hydrolyzates) were synthesized using the reverse reaction of α-galactosidase from Candida guilliermondii H-404. The α-GOS A and B were isolated and their structures were identified by methylation analysis. The main product of the disaccharides in α-GOS A and α-GOS B was the (1, 6)-isomer. The remaining disaccharides consisted of (1, 3)-, (1, 2)-, and (1, 1)-isomers. Conditions for synthesis of α-GOS B from lactose hydrolyzates were examined. The yield of α-GOS B was approximately 20% when the mixture of heat-treated cells containing a-galactosidase (60U/g galactose) and 85% lactose hydrolyzates was incubated for 90 h at pH 4.5 and 50°C. The α-GOS A and B were available as the donor substrates in transgalactosylation of α-galactosidase in the same manner as melibiose. 相似文献
17.
Monique Decastel Anh-Tuan Tran Jean-Pierre Frénoy 《Biochemical and biophysical research communications》1982,106(2):638-643
The binding of 4-methylumbelliferyl-α-D-galactopyranoside, -β-D-galactopyranoside and -D-Galβ(1→3)DGalNac to peanut agglutinin was studied by fluorescence. Peanut agglutinin quenched the fluorescence intensity of 4-methylumbelliferyl-α-D-galactopyranoside but enhanced that of the two 4-methylumbelliferyl-β-galactosides. For α-D-galactopyranoside, the association constants measured at 4 and 25°C were 3.4 × 103 and 1.7 × 103 M?1 respectively, and for D-Galβ(1→3)DGalNac, 1.5 × 105 and 3.3 × 104 M?1. The binding enthalpies estimated from these values are consistent with the existence of extended sugar binding sites in the peanut agglutinin molecule. 相似文献
18.
Satoshi Tahara Masaki Kudo Junya Mizutani 《Bioscience, biotechnology, and biochemistry》2013,77(12):2627-2628
The sex pheromone of the citrus mealybug (Pseudococcus cryptus), [(1R,3R)-3-isopropenyl-2,2-dimethylcyclobutyl]methyl 3-methyl-3-butenoate, was synthesized from (+)-α-pinene in five operational steps in a 43% overall yield. The synthetic pheromone was identical with the natural pheromone in 1H-NMR and mass spectroscopic properties, and showed almost the same pheromonal activity as the natural pheromone. 相似文献
19.
《Bioscience, biotechnology, and biochemistry》2013,77(4):912-920
Small-sized isolectins (9 KDa) from Hypnea japonica belong to a new lectin family. Here, we describe the carbohydrate-binding properties of the three isolectins (hypninA1, A2, and A3) and the amino acid sequence of hypninA3 (P85888). In frontal affinity chromatography with about 100 pyridylaminated oligosaccharides, the isolectins, which had no affinity for monosaccharides, commonly bound only core (α1-6) fucosylated N-glycans, and did not the other oligosaccharides examined, including (α1-2), (α1-3), and (α1-4) fucosylated glycans. The specific binding of hypninA3 with the fucosylated N-glycans (K a; 0.52–7.58×106 M?1) was confirmed by surface plasmon resonance analyses on an immobilized glycoprotein with and without core (α1-6) fucose. Such specificity of hypninA is clearly distinct from those of other known fucose-binding lectins, making it a valuable tool for cancer diagnosis and quality control of medicinal antibodies. HypninA3 is a polypeptide composed of 90 amino acids containing four half-cystines. 相似文献
20.
Olga A. Valueva Evelina L. Zdorovenko Vadim V. Kachala Liudmyla D. Varbanets Nikolay P. Arbatsky Vladimir V. Shubchynskyy Alexander S. Shashkov Yuriy A. Knirel 《Carbohydrate research》2011,(1):146
The following structure of the O-polysaccharide of Pragia fontium 27480 was elucidated by sugar analysis, including determination of the absolute configurations of the monosaccharides, and Smith degradation along with 1D and 2D 1H and 13C NMR spectroscopy:→4)-β-d-ManpNAc3NAcA-(1→2)-α-l-Rhap-(1→3)-β-l-Rhap-(1→4)-α-d-GlcpNAc-(1→where ManNAc3NAcA stands for 2,3-diacetamido-2,3-dideoxymannuronic acid. 相似文献