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1.
Emiko Matsunaga Yujiro Higuchi Kazuki Mori Nao Yairo Saki Toyota Takuji Oka 《Bioscience, biotechnology, and biochemistry》2017,81(7):1314-1319
As a constituent of polysaccharides and glycoconjugates, β-d-galactofuranose (Galf) exists in several pathogenic microorganisms. Although we recently identified a β-d-galactofuranosidase (Galf-ase) gene, ORF1110, in the Streptomyces strain JHA19, very little is known about the Galf-ase gene. Here, we characterized a strain, named JHA26, in the culture supernatant of which exhibited Galf-ase activity for 4-nitrophenyl β-d-galactofuranoside (pNP-β-d-Galf) as a substrate. Draft genome sequencing of the JHA26 strain revealed a putative gene, termed ORF0643, that encodes Galf-ase containing a PA14 domain, which is thought to function in substrate recognition. The recombinant protein expressed in Escherichia coli showed the Galf-specific Galf-ase activity and also released galactose residue of the polysaccharide galactomannan prepared from Aspergillus fumigatus, suggesting that this enzyme is an exo-type Galf-ase. BLAST searches using the amino acid sequences of ORF0643 and ORF1110 Galf-ases revealed two types of Galf-ases in Actinobacteria, suggesting that Galf-specific Galf-ases may exhibit discrete substrate specificities. 相似文献
2.
Stefan Evers Barbara Casadewall Murielle Charles Sylvie Dutka-Malen Marc Galimand Patrice Courvalin 《Journal of molecular evolution》1996,42(6):706-712
Thed-alanine:d-alanine-ligase-related enzymes can have three preferential substrate specificities. Usually, these enzymes synthesized-alanyl-d-alanine. In vancomycin-resistant Gram-positive bacteria, structurally related enzymes synthesized-alanyl-d-lactate or Dalanyl-d-serine. The sequence of internal fragments of eight structurald-alanine:d-alanine ligase genes from enterococci has been determined. Alignment of the deduced amino acid sequences with those of other
related enzymes from Gram-negative and Gram-positive bacteria revealed the presence of four distinct sequence patterns in
the putative substrate-binding sites, each correlating with specificity to a particular substrate (d-alanine:d-lactate ligases exhibited two patterns). Phylogenetic analysis showed different clusters. The enterococcal subtree was largely
superimposable on that derived from 16S rRNA sequences. In lactic acid bacteria, structural divergence due to differences
in substrate specificity was observed. Glycopeptide resistance proteins VanA and VanB, the VanC-type ligases, and Dd1A and
DdlB from enteric bacteria andHaemophilus influenzae constituted separate clusters.
Correspondence to: P. Courvalin 相似文献
3.
Albert M. Wu 《Molecular and cellular biochemistry》1984,61(2):131-1411
Summary The binding properties of Arachis hypogaea (PNA), Bauhinia vurpurea alba (BPL), Maclura pomifera (MPL) and Sophora japonica (SJL) lectins were studied by quantitative precipitin and precipitin inhibition assays, demonstrating them to be most specific for dGal13dGalNAc residues. Additionally, each lectin had its own binding characteristic such as different binding abilities to dGal14dGlcNAc or dGal13dGlcNAc1linked oligosaccharides, and/or dGalNAc1linked to the Ser or Thr of the protein moiety. These differential binding characteristics can be used for investigating fine differences of the carbohydrate structure of the glycoconjugates, especially those having dGal13dGalNAc residues as terminal non-reducing ends.Abbreviations
dGal
d-galactopyranose
-
dMan
d-mannopyranose
-
dGalNAc
2-acetamido-2-deoxy-d-galacto-pyranose
-
dGlcNAc
2-acetamino-2-deoxy-d-glucopyranose
- LFuc
L-fucose
- NeuNAc
N-acetylneuraminic acid
- Ser
serine
- Thr
Threonine
- RCA
Ricinus communis agglutinin
- SBA
Soy bean agglutinin (Glycine max)
- HPA
Helix pomatia agglutinin
- DBL
Dolichos biflorus lectin
- GCL
Geodia cydonium lectin 相似文献
4.
A Gal1-4GlcNAc (2-6)-sialyltransferase from human liver was purified 34 340-fold with 18% yield by dye chromatography on Cibacron Blue F3GA and cation exchange FPLC. The enzyme preparation was free of other sialyltransferases. It did not contain CMP-NeuAc hydrolase, protease, or sialidase activity, and was stable at –20°C for at least eight months. The donor substrate specificity was examined with CMP-NeuAc analogues modified at C-5 or C-9 of theN-acetylneuraminic acid moiety. Affinity of the human enzyme for parent CMP-NeuAc and each CMP-NeuAc analogue was substantially higher than the corresponding Gal1-4GlcNAc (2-6)-sialyltransferase from rat liver.Abbreviations FPLC
fast protein liquid chromatography
- NeuAc
5-N-acetyl-d-neuraminic acid
- 9-amino-NeuAc
5-acetamido-9-amino-3,5,9-trideoxy-d-glycero-2-nonulosonic acid
- 9-acetamido-NeuAc
5,9-diacetamido-3,5,9-trideoxy-d-glycero--d-2-nonulosonic acid
- 9-benzamido-NeuAc
5-acetamido-9-benzamido-3,5,9-trideoxy-d-glycero--d-galacto-2-nonulosonic acid
- 9-fluoresceinyl-NeuAc
9-fluoresceinylthioureido-NeuAc
- 5-formyl-Neu
5-formyl--d-neuraminic acid
- 5-aminoacetyl-Neu
5-aminoacetyl--d-neuraminic acid
- CMP-NeuAc
cytidine-5-monophospho-N-acetylneuraminic acid
- GM1
Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc-ceramide
- ST
sialyltransferase
- DTE
1,4-dithioerythritol
Enzyme: Gal1-4GlcNAc (2-6)-sialyltransferase, EC 2.4.99.1. 相似文献
5.
α- or β-Galactofuranosyl (Galf) amides can be synthesized with high stereoselectivity by traceless Staudinger ligation starting from unprotected β-galactofuranosyl azide or tetra-O-acetyl-β-galactofuranosyl azide, respectively. The resulting Galf amides are hitherto unknown molecules, with interesting potential as inhibitors of mycobacterial growth. 相似文献
6.
Tsutomu Takayanagi Katsuhiko Kushida Kyoko Idonuma Katsumi Ajisaka 《Glycoconjugate journal》1992,9(5):229-234
Structures of oligosaccharides fromAspergillus niger -d-galactosidase [EC 3.2.1.22] were studied. Purified -d-galactosidase was treated withN-glycosidase F, and six kinds of oligosaccharides were isolated by gel chromatography and anion-exchange chromatography. The structures of the oligosaccharides were determined by1H-NMR and compositional analysis to be Man5GlcNAc2, Man6GlcNAc2, Man9GlcNAc2, GlcMan9GlcNAc2, GalMan4GlcNAc2 and GalMan5GlcNAc2. From mild acid hydrolysis, methylation analysis and ROESY spectral analysis, it was ascertained that the galactosyl residue in two oligosaccharides was in the furanose form and was bound to mannose at the nonreducing end with an 1–2 linkage (GalfMan4GlcNAc2 and GalfMan5GlcNAc2). 相似文献
7.
S. Wiley H. Felbeck 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(7):561-569
The chemoautotrophic symbiont-bearing clam Lucinoma aequizonata contains very high levels of free d-alanine in all tissues. The possible sources for this amino acid and its involvement in the clams' metabolism were investigated. Very low levels of d-alanine (generally below 1 mol·l-1) were measured in the sediment porewaters from the habitat of the clams. Experiments with 14C-labeled tracers demonstrate an active metabolism of d-alanine in the clams rather than a role as inert waste product. d-alanine is metabolized at about 0.12 mol·g fw-1·h-1. Label from aspartate, but not glucose and CO2, is incorporated into d-alanine. Incubation with labeled d-alanine did not result in formation of radioactive l-alanine. Tests for alanine racemase (EC 5.1.1.1) and d-amino acid oxidase (EC 1.4.3.3.) did not show activity in either gill, i.e. symbiont and host, or foot tissue. d-Alanine amino transferase (EC 2.6.1.b.) was demonstrated in gill and foot tissues. Two sources for d-alanine are proposed: a degradation of cell walls of symbiotic bacteria and production by the host using a d-specific alanine transaminase.Abbreviations aa
amino acid(s)
- fw
fresh weight
- HPLC
high-performance liquid chromatography
- MBH
methyl benzethonium hydroxyde
- NAC
N-acetyl-l-cysteine
- OPA
ortho-phthaldialdehyde
- TCA
tricarbonic acid 相似文献
8.
Jacopo F. Novelli Kshitiz Chaudhary Julie Canovas Jack S. Benner Catherine L. Madinger Paul Kelly Jonathan Hodgkin Clotilde K.S. Carlow 《Developmental biology》2009,335(2):340-355
Galactofuranose (Galf), the furanoic form of d-galactose produced by UDP-galactopyranose mutases (UGMs), is present in surface glycans of some prokaryotes and lower eukaryotes. Absence of the Galf biosynthetic pathway in vertebrates and its importance in several pathogens make UGMs attractive drug targets. Since the existence of Galf in nematodes has not been established, we investigated the role of the Caenorhabditis elegans UGM homolog glf-1 in worm development. glf-1 mutants display significant late embryonic and larval lethality, and other phenotypes indicative of defective surface coat synthesis, the glycan-rich outermost layer of the nematode cuticle. The glf homolog from the protozoan Leishmania major partially complements C. elegans glf-1. glf-1 mutants rescued by L. major glf, which behave as glf-1 hypomorphs, display resistance to infection by Microbacterium nematophilum, a pathogen of rhabditid nematodes thought to bind to surface coat glycans. To confirm the presence of Galf in C. elegans, we analyzed C. elegans nucleotide sugar pools using online electrospray ionization–mass spectrometry (ESI-MS). UDP-Galf was detected in wild-type animals while absent in glf-1 deletion mutants. Our data indicate that Galf likely has a pivotal role in maintenance of surface integrity in nematodes, supporting investigation of UGM as a drug target in parasitic species. 相似文献
9.
Marco Scocchi Christine Lüthy Pietro Decarli Giuseppina Mignogna Philipp Christen Renato Gennaro 《International journal of peptide research and therapeutics》2009,15(2):147-155
Bac7, a cathelicidin peptide of the proline-rich group, inactivates bacteria in a stereospecific manner by entering target
cells without any apparent membrane damage and by binding to as yet unknown intracellular targets. The present study was aimed
at detecting these putative intracellular interactors, which might mediate the antibacterial action of this peptide. By using
affinity resins functionalized with the N-terminal 1-35 fragment of Bac7, a single protein was specifically retained with
high affinity from Escherichia coli cytoplasmic protein lysates. This ligand was identified as the heat shock protein DnaK, the Hsp70 homolog in E. coli. The interaction between the peptide and the chaperone is stereospecific, given that a resin prepared with the all-
d enantiomer failed to retain the protein. In vitro, Bac7(1-35) formed a complex with DnaK with an affinity comparable to that
of other known high-affinity peptide ligands. In addition, at 10–100 μM concentration, the peptide inhibited the protein refolding
activity of the complete DnaK/DnaJ/GrpE/ATP molecular chaperone system in a dose-dependent manner. Despite these results,
the in vitro sensitivity to the peptide, under growth permitting conditions, of DnaK-deficient E. coli strains was not significantly affected compared to the wild-type strain. This suggests that, apart from DnaK, other vital
targets for the proline-rich AMPs are present in susceptible bacteria.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Marco Scocchi and Christine Lüthy contributed equally to this work. 相似文献
10.
Elin Säwén Eine Huttunen Xue Zhang Zhennai Yang Göran Widmalm 《Journal of biomolecular NMR》2010,47(2):125-134
The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in
situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects
of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides
were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT
experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 →, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently
are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two
terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined
using translational diffusion experiments which resulted in Mw = 62 kDa, corresponding to 64 repeating units in the EPS. 相似文献
11.
Tada R Tanioka A Iwasawa H Hatashima K Shoji Y Ishibashi K Adachi Y Yamazaki M Tsubaki K Ohno N 《Glycoconjugate journal》2008,25(9):851-861
A β-d-glucan obtained from Aureobasidium pullulans (AP-FBG) exhibits various biological activities: it exhibits antitumour and antiosteoporotic effects and prevents food allergies.
An unambiguous structural characterisation of AP-FBG is still awaited. The biological effects of β-d-glucan are known to depend on its primary structures, conformation, and molecular weight. Here, we elucidate the primary
structure of AP-FBG by NMR spectroscopy, and evaluate its biological activities. Its structure was shown to comprise a mixture
of a 1-3-β-d-glucan backbone with single 1-6-β-d-glucopyranosyl side-branching units every two residues (major structure) and a 1-3-β-d-glucan backbone with single 1-6-β-d-glucopyranosyl side-branching units every three residues (minor structure). Furthermore, this β-d-glucan exhibited immunostimulatory effects such as the accumulation of immune cells and priming effects against enterobacterium.
To our knowledge, 1-3-β-glucans like AP-FBG with such a high number of 1-6-β-glucopyranosyl side branching have a unique structure;
nevertheless, many 1-3-β-glucans were isolated from various sources, e.g. fungi, bacteria, and plants. 相似文献
12.
Jinghua Yang Nirav Y. Shelat C. Allen Bush John O. Cisar 《The Journal of biological chemistry》2010,285(31):24217-24227
Although closely related at the molecular level, the capsular polysaccharide (CPS) of serotype 10F Streptococcus pneumoniae and coaggregation receptor polysaccharide (RPS) of Streptococcus oralis C104 have distinct ecological roles. CPS prevents phagocytosis of pathogenic S. pneumoniae, whereas RPS of commensal S. oralis functions as a receptor for lectin-like adhesins on other members of the dental plaque biofilm community. Results from high resolution NMR identified the recognition region of S. oralis RPS (i.e. Galfβ1–6GalNAcβ1–3Galα) in the hexasaccharide repeat of S. pneumoniae CPS10F. The failure of this polysaccharide to support fimbriae-mediated adhesion of Actinomyces naeslundii was explained by the position of Galf, which occurred as a branch in CPS10F rather than within the linear polysaccharide chain, as in RPS. Carbohydrate engineering of S. oralis RPS with wzy from S. pneumoniae attributed formation of the Galf branch in CPS10F to the linkage of adjacent repeating units through sub terminal GalNAc in Galfβ1–6GalNAcβ1–3Galα rather than through terminal Galf, as in RPS. A gene (wcrD) from serotype 10A S. pneumoniae was then used to engineer a linear surface polysaccharide in S. oralis that was identical to RPS except for the presence of a β1–3 linkage between Galf and GalNAcβ1–3Galα. This polysaccharide also failed to support adhesion of A. naeslundii, thereby establishing the essential role of β1–6-linked Galf in recognition of adjacent GalNAcβ1–3Galα in wild-type RPS. These findings, which illustrate a molecular approach for relating bacterial polysaccharide structure to function, provide insight into the possible evolution of S. oralis RPS from S. pneumoniae CPS. 相似文献
13.
《Bioscience, biotechnology, and biochemistry》2013,77(2):312-319
The soluble and insoluble fractions obtained after sonication and centrifugation of Bifidobacterium adolescentis M101–4 cells were examined, and both of these fractions exhibited mitogenic activity in art assay of murine splenocytes and Peyer’s patch cells in vitro. The soluble fraction was further treated by a 6-step procedure involving proteinase K-treatment, ultrafiltration with a 50-kDa cut-off molecular-sieving membrane, anion-exchange chromatography, dialysis, ultrafiltration through a 6-kDa cut-off membrane filter, and gel-filtration to yield a soluble high molecular weight fraction (SHF) which was effective for stimulating the proliferation of murine splenocytes. Almost three quarters of this fraction by weight was found to consist of carbohydrates containing glucose and galactose as major constituents, and the average molecular weight was estimated to be between 60,000 and 2,460,000, with the main peak at 1,550,000 Da, by the retention time of gel permeation chromatography. A structural analysis by 1H- and 13C-nuclear magnetic resonance and methylation indicated that SHF contained polysaccharides consisting of -4Galp1-, -4Glcp1-, and -6Glcp1- as the major residues, and Galf1- and -6Galf1- as the minor residues. Immunopotentiating SHF was found to contain galactofuranosyl residues as characteristic constituents which had not been previously detected in other soluble fractions from Gram-positive bacteria. 相似文献
14.
The occurrence of a new bacterial dehalogenase acting on both the optical isomers of 2-halogenated alkanoic acids was demonstrated. When the haloalkanoic acid-utilizing bacteria were screened in a medium containing dl-2-chloropropionate as a sole carbon source, two types of bacteria were isolated: (1) a few strains utilizing both d- and l-isomers of 2-chloropropionate and (2) strains utilizing only the l-isomer. A dehalogenating enzyme was obtained from the cells of Pseudomonas sp. which is able to utilize both isomers. The crude enzyme catalyzed the dehalogenation of d- and l-2-chloropropionates to yield l- and d-isomers of lactate, respectively. The enzyme showed the same pH optimum and heat inactivation rate for the d- and l-isomers. Apparent K
m values for d- and l-2-chloropropionates were 4.5 and 1.0 mM, respectively. The enzyme acted specifically on 2-haloalkanoic acids. Activity staining of disc-gels electrophoresed witg the crude enzyme preparation showed that the dehalogenation of d- and l-2-chloropropionates, monochloroacetate, dichloroacetate, 2,2-dichloropropionate, and dl-2-chlorobutyrate is due to a single protein.Abbreviations MCA
monochloroacetic acid
- DCA
dichloroacetic acid
- TCA
trichloroacetic acid
- 2 MCPA
2-monochloropropionic acid
- 22 DCPA
2,2-dichloropropionic acid
- 3 MCPA
3-monochloropropionic acid
- 2 MCBA
2-monochlorobutyric acid
- 3 MCBA
3-monochlorobutyric acid
- 4 MCBA
4-monochlorobutyric acid 相似文献
15.
We demonstrate that 9-amino-NeuAc transferred to asialo-1-acid glycoprotein resists cleavage by bacterial, viral and mammalian sialidases. This is the first synthetic sialic acid analogue, which can be activated and transferred to glycoprotein, but is not a sialidase (EC 3.2.1.18) substrate.Abbreviations HPLC
high performance liquid chromatography
- BSA
bovine serum albumin
- NeuAc
N-acetyl-d-neuraminic acid, 5-acetamido-3,5-dideoxy-d-glycero-d-galacto-non-2-ulosonic acid
- 9-Amino-NeuAc
9-amino-5-N-acetyl-d-neuraminic acid, 5-acetamido-9-trideoxy-d-glycero-d-galacto-non-2-ulosonic acid
- CMP-NeuAc
cytidine-5-monophospho-N-acetyl-d-neuraminic acid
- CMP-9-amino-NeuAc
cytidine-5-monophospho-9-amino-5-N-acetyl-d-neuraminic acid
- 9-azido-NeuAc
5-acetamido-9-azido-3,5,9-trideoxy-d-glycero-d-galacto-non-2-ulosonic acid.
Enzymes EC 3.2.1.18
sialidase, acylneuraminylhydrolase
- EC 2.4.99.1
Galß1-4GlcNAc a(2-6)-sialytransferase 相似文献
16.
Inka Brockhausen Dale Toki Jennifer Brockhausen Stefan Peters Tim Bielfeldt Astrid Kleen Hans Paulsen Morten Meldal Fred Hagen Lawrence A. Tabak 《Glycoconjugate journal》1996,13(5):849-856
The factors determining glycosylation of mucin type glycoproteins are not well understood. In the present work, we investigated the role of the peptide moiety and of the presence of O-glycan chains on O-glycosylation by UDP-GalNAc: polypeptide -N-acetylgalactosaminyl-transferase (ppGalNAc-T). We used purified ppGalNAc-T from bovine colostrum and a series of synthetic glycopeptide and peptide substrates most of which contained sequences derived from the tandem repeat region of MUC2 mucin. The rate of incorporation of GalNAc into Thr was significantly greater than toward Ser residues. The presence of one or two GalNAc-Thr moieties in the substrate significantly reduced enzyme activity, and this effect was more pronounced when the disaccharide Gal1–3GalNAc was present. Thus the sequential attachment of a second GalNAc residue in the vicinity of a pre-existing GalNAc-Thr or Gal1–3GalNAc-Thr occurs at a slower rate than primary glycosylation of carbohydrate-free peptide. Analysis of products by HPLC showed that the enzyme was selective in glycosylating peptides or glycopeptides with the PTTTPIST sequence in that the preferred primary glycosylation site was the third Thr from the aminoterminal end; secondary glycosylation depended on the site of the primary glycosylation. Negatively but not positively charged amino acids on the carboxy-terminal side of the putative secondary glycosylation site resulted in high activity suggesting charge-charge interactions of substrates with the enzyme. These studies indicate that O-glycosylation by bovine colostrum ppGalNAc-T is a selective process dependent on both the amino acid sequence and prior glycosylation of peptide substrates.Abbreviations Gal
G,d-galactose
- GalNac
N-acetyl-d-galactosamine
- HPLC
high performance liquid chromatography
- ppGalNAc-T
UDP-GalNAc: polypeptide -GalNAc-transferase EC 2.4.1.41
- SerGalNAc
GalNAc-Ser
- ThrGalNac
GalNAc-Thr 相似文献
17.
Taiki Futagami Karina Kizjakina Pablo Sobrado Keisuke Ekino Kaoru Takegawa Masatoshi Goto Yoshiyuki Nomura Takuji Oka 《Molecular microbiology》2013,90(5):1054-1073
The cells walls of filamentous fungi in the genus Aspergillus have galactofuranose (Galf)‐containing polysaccharides and glycoconjugates, including O‐glycans, N‐glycans, fungal‐type galactomannan and glycosylinositolphosphoceramide, which are important for cell wall integrity. Here, we attempted to identify galactofuranosyltransferases that couple Galf monomers onto other wall components in Aspergillus nidulans. Using reverse‐genetic and biochemical approaches, we identified that the AN8677 gene encoded a galactofuranosyltransferase, which we called GfsA, involved in Galf antigen biosynthesis. Disruption of gfsA reduced binding of β‐Galf‐specific antibody EB‐A2 to O‐glycosylated WscA protein and galactomannoproteins. The results of an in‐vitro Galf antigen synthase assay revealed that GfsA has β1,5‐ or β1,6‐galactofuranosyltransferase activity for O‐glycans in glycoproteins, uses UDP‐d ‐Galf as a sugar donor, and requires a divalent manganese cation for activity. GfsA was found to be localized at the Golgi apparatus based on cellular fractionation experiments. ΔgfsA cells exhibited an abnormal morphology characterized by poor hyphal extension, hyphal curvature and limited formation of conidia. Several gfsA orthologues were identified in members of the Pezizomycotina subphylum of Ascomycota, including the human pathogen Aspergillus fumigatus. To our knowledge, this is the first characterization of a fungal β‐galactofuranosyltransferase, which was shown to be involved in Galf antigen biosynthesis of O‐glycans in the Golgi. 相似文献
18.
Bernard Priem Julien Solokwan Jean-Michel Wieruszeski Gérard Strecker Hassan Nazih Henri Morvan 《Glycoconjugate journal》1990,7(2):121-132
The oligosaccharides Man5GlcNAc and Man3(Xyl)GlcNAc(Fuc)GlcNAc presumed to originate fromN-glycosyl proteins have been purified from an extracellular medium (concentration: 2–5 mg/l of 14 day cultures) of white campion (Silene alba) suspension culture. Their primary structures have been determined by1H-400-MHz NMR spectroscopy and FAB-MS spectrometry. They are probably the result of an autophagic process including protein catabolism due to sucrose starvation. Additional identification of digalactosylglycerol (galactolipid breakdown) argues for this hypothesis.Abbreviations Fuc
l-fucose
- Man
d-mannose
- Xyl
d-xylose
- GlcNAc
N-acetyl-d-glucosamine
- Gal
d-galactose
- Glc
d-glucose
- FAB-MS
fast atom bombardment mass spectrometry
- NMR
nuclear magnetic resonance 相似文献
19.
Vassiliki Magafa Lenka Borovičková Jiřina Slaninová Paul Cordopatis 《Amino acids》2010,38(5):1549-1559
We report the solid phase synthesis and some pharmacological properties of 24 oxytocin (OT) analogues. Basic modifications
at position 9 (introduction of l- or d-β-(2-thienyl)-alanine [L- or D-Thi], or l- or d-3-Pyridylalanine [l- or d-3-Pal]) were combined with d-tyrosine(OEthyl) [d-Tyr(Et)] or d-1-naphthylalanine [d-1-Nal] in position 2 and β-mercaptopropionic acid (Mpa) in position 1 modifications in altogether 14 analogues. Additionally, 8 analogues having α-aminoisobutyric acid [Aib] or d-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (d-Tic) or diethylglycine (Deg) in position 9 and d-Tyr(Et) or d-1-Nal or d-Tic in position 2 and Mpa or Pen (ββ-dimethylcysteine) in position 1 were prepared. Two of these analogues have one more modification in position 6, i.e. Pen.
Furthermore, two analogues having Mpa in position 1 and d-Tyr(Et) or d-1-Nal in position 2 were prepared for comparison purposes. The analogues were tested for rat uterotonic activity in vitro,
in the rat pressor assay and for binding affinity to human OT receptor. The analogue having the highest anti-oxytocic activity
was [Mpa1, d-Tyr(Et)2, Deg9]OT (pA2 = 8.68 ± 0.26); this analogue was also selective. 相似文献
20.
Tamiaki H Komada J Kunieda M Fukai K Yoshitomi T Harada J Mizoguchi T 《Photosynthesis research》2011,107(2):133-138
Bacteriochlorophyll(BChl)-f which has not yet been found in natural phototrophs was prepared by chemically modifying chlorophyll-b. The retention time of reverse-phase high-performance liquid chromatography of the synthetic monomeric BChl-f as well as its visible absorption and fluorescence emission spectra in a solution were identified and compared with other
naturally occurring chlorophyll pigments obtained from the main light-harvesting antenna systems of green sulfur bacteria,
BChls-c/d/e. Based on the above data, BChl-f was below the level of detection in three strains of green photosynthetic bacteria producing BChl-e. 相似文献