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1.
The interactions between a series of platinum complexes, including (pyridyl)(6-phenyl-2,2-bipyridine)platinum(II) hexafluorophosphate (1), three dinuclear bis[(6-phenyl-2,2-bipyridine)platinum(II)] complexes (2–4), and (4-aminopyridine)(4,6-diphenyl-2,2-bipyridine)platinum(II) perchlorate (5) with DNA have been investigated. All Pt(II) complexes, except 5, were demonstrated to be DNA intercalators, based on viscosity measurements. Absorption and fluorescence titration results indicated that the addition of a phenyl ring to the 6-phenyl-2,2-bipyridine ligand dramatically reduced the DNA binding of the Pt(II) complex
5. The dinuclear complexes
2–4 exhibited multiple binding modes of mono/bisintercalation and groove binding, as revealed by viscosity and fluorescence titration measurements. While complexes
2–4 bound to DNA with significantly enhanced affinities as compared to 1, compounds
1 and 2–4 showed similar IC50 values against a panel of cancer cell lines. In addition, these complexes showed similar cellular uptakes. The results indicated that the cytotoxicity of these (6-phenyl-2,2-bipyridine)platinum compounds may not be mediated through DNA binding but may involve interacting mechanisms with cellular components other than DNA.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.Abbreviations AO
acridine orange
- ampy
4-aminopyridine
- bipy
2,2-bipyridine
- bp
base pair
- CNN
6-phenyl-2,2-bipyridine
- ctDNA
calf thymus DNA
- EB
ethidium bromide
- EI
electron ionization
- en
ethylenediamine
- FAB
fast atomic bombardment
- H33342
Hoechst 33342
- IC50
inhibitory concentration 50%
- ICP-AES
inductively coupled plasma–atomic emission spectroscopy
- MTT
3-(4,5-dimethylthiazol-2-yl)-2,5-tetrazolium bromide
- 4-PhCNN
4,6-diphenyl-2,2-bipyridine
- phen
1,10-phenanthroline
- terpy
2,2:6,2-terpyridine
- Tris
tris(hydroxymethyl)aminomethane 相似文献
2.
Robert P. Walker Wanda M. Waterworth Michael H. Beale Richard Hooley 《Plant Growth Regulation》1994,15(3):271-279
Aleurone protoplasts of wild oat (Avena fatua L.), and subcellular fractions isolated from them, were photoaffinity labeled using the synthetic gibberellin (GA) derivative GA4-17-yl-1-(1-thia)propan-3-ol-4-azido-5-[125I]iodosalicylate. Labeled polypeptides were identified by electrophoresis under denaturing conditions followed by autoradiography. GA-photoaffinity labeling of both intact protoplasts and isolated subcellular fractions led to the covalent attachment of the reagent to many polypeptides. A 50 kD polypeptide in the soluble fraction of homogenates of aleurone protoplasts GA-photoaffinity labeled in vivo showed specific binding. The biologically active GA1, GA4 and GA4-17-yl-1(1-thia)propan-3-ol-4-azidosalicylate completed for binding whereas the biologically inactive GA8 and GA34 did not. The GA-photoaffinity labeling characteristics of this polypeptide suggested that it might interact specifically with biologically active GAs in vivo. Attempts to detect specific GA-binding in in vitro GA-photoaffinity labeling experiments met with only limited success perhaps indicating the labile nature of specific binding observed in vivo. The potential of GA-photoaffinity labeling for identifying GA-binding proteins in aleurone and other GA-responsive tissues is discussed.Abbreviations azido IAA =
5-azido-7-[3H]indole-3-acetic acid
- azido NPA =
5-azido-[3,6-3H]1-N-napthylpthalamic acid
- BTP =
1,3-bis(Tris(hydroxymethyl)methylamino)-propane
- GA4-O-ASA =
GA4-17-yl-1-(1-thia)propane-3-ol-4-azidosalicylate
- [125I]GA4-O-ASA =
GA4-17-yl-1-(1-thia)propan-3-ol-4-azido-5-[125I]iodosalicylate
- NPA =
1-Naphthylphthalmic acid
- PAGE =
Polyacrylamide gel electrophoresis
- PMSF =
phenylmethylsulfonyl fluoride
- SDS =
Sodium dodecyl sulphate
- TLCK =
L-1-Chloro-3-(4-tosylamido)-7-amino-2-heptanone-HCl 相似文献
3.
Dr Jean-Charles Cailliez Cristina Cantelli Nathalie Séguy Stefania Conti Mara Gerloni Giulia Morace Luciano Polonelli 《Mycopathologia》1994,126(3):173-177
A secreted killer toxin was detected through the cell wall ofPichia anomala cells by ultrastructural immunodetection with a specific monoclonal antibody (MAb KT4). MAb KT4 was successively detected by colloidal gold labeled streptavidin and biotinylated anti-mouse F(ab')2 antibodies. The antigenic determinants of the toxin were localized throughout the cytoplasm and the cell wall of killer yeast cells. The Lowicryl K4M-immunogold method gave very satisfactory results and showed that the killer toxin was somewhat concentrated in the yeast cell wall layers before being exported into the medium. In agreement with previous reports, the binding of MAb KT4 suggested that theP. anomala killer toxin secretion did not result from a homogeneous diffusion across the yeast cell wall.Abbreviations G15
gold particles of 15 nm
- IEM
immunoelectron microscopy
- IFA
immunofluorescence assay
- MAb
monoclonal antibody
- PBS
phosphate buffered saline
- SAM/F(ab)2
sheep antibodies anti-mouse F(ab)2
- SBB
Sabouraud buffered broth 相似文献
4.
Thierry Maillet Annie-Claude Roche Fabienne Thérain Michel Monsigny 《Cancer immunology, immunotherapy : CII》1985,19(3):177-182
Summary In vivo localization of a mouse monoclonal antibody (F2-10.23 IgM) binding leukemic L 1210 cells was studied in DBA/2 mice bearing an L 1210 tumor. F(ab)2 fragments were prepared and their specific binding to L 1210 cells was analyzed by flow cytofluorometry. Radiolocalization studies were performed by using 125I- or 131I-labeled IgM monoclonal antibody or its F(ab')2 fragments to ascertain their capacity to visualize the L 1210 tumor. F(ab)2 fragments were cleared more rapidly than the whole IgM; the clearance was as fast in healthy as in tumor-bearing mice. The tumor-to-muscle ratio observed 24 h after injection of 125I-radiolabeled F(ab)2 fragments and 125I-radiolabeled IgM was 10; the radioactivity level in the blood with F(ab)2 fragments was lower than with IgM, and so -camera imaging was workable with F(ab)2 fragments without background substraction. The tumor localization was studied over a period of 5 days by recording the distribution of the iodinated fragments in the tumor-bearing leg compared with that in the normal leg, and by computer analysis of the region of interest. F(ab)2 fragments gave better results than intact IgM in tumor visualization. Nevertheless, the rapid clearance of this antibody or its F(ab)2 fragments make them hardly suitable as carriers of toxic drugs.
Abbreviations used are: MEM Minimum essential medium; SDS sodium dodecylsulfate; PAGE polyacrylamide gel electrophoresis 相似文献
5.
Neisseria gonorrhoeae that resist complement-dependent killing by normal human serum (NHS) are sometimes killed by immune convalescent sera from patients recovering from disseminated gonococcal infection (DGI). In these studies, killing by immune serum was prevented or blocked by immunoglobulin G (IgG) or F(ab)2 isolated from NHS. Purified human IgG antibodies directed against gonococcal protein III, contained most of the blocking activity in IgG. In addition, immune convalescent DGI serum, which did not exhibit bactericidal activity, was restored to killing by selective immunodepletion of protein III antibodies. Blocking IgG or F(ab)2 prepared from IgG, partially inhibited binding of bactericidal antibody to N. gonorrhoeae. Also, binding of a monoclonal antibody recognizing N. gonorrhoeae outer membrane protein PIII was almost completely inhibited by blocking F(ab)2.Presensitization of N. gonorrhoeae with increasing concentrations of blocking IgG or F(ab)2 before incubation with bactericidal antibody and an antibody free source of complement, increased consumption and deposition of the third component of human complement (C3) and the ninth component of complement (C9) but inhibited killing in dose-related fashion. 相似文献
6.
Alan Shaver Jesse B. Ng David A. Hall Barry I. Posner 《Molecular and cellular biochemistry》1995,153(1-2):5-15
The inorganic coordination chemistry of peroxovanadium compounds relevant to insulin mimesis is reviewed. The structure and kinetic reactivity of solutions of vanadate anion, vanadyl complexes and peroxovanadate complexes are briefly compared. Peroxovanadium compounds contain an oxo group, one or two peroxo ligands (O2
2–) and an ancillary ligand which is usually bidentate. These compounds approximate a trigonal bipyramidal structure which can be divided conceptually into a polar oxo half and a relatively non-polar organic half. This presents a number of interesting design variations which are discussed with respect to the development of a rudimentary structure-activity correlation of insulin mimetic ability.Abbreviations phen
1,10-phenanthroline
- 4,7-Me2phen
4,7-dimethyl-1,10-phenanthroline
- 3,4,7,8-Me4phen
3,4,7,8-tetramethyl-1,10-phenanthroline
- 5-CH3phen
5-methyl-1,10-phenanthroline
- 5-NO2phen
5-nitro-1,10-phenanthroline
- 5-NH2phen
5-amino-1,10-phenanthroline
- bipy
2,2-bipyridine
- bipyH
2,2-bipyridinium
- 4,4-Me2bipy
4,4-dimethyl-2,2-bipyridine
- bipy-4,4-(COO)2
2,2-bipyridine-4,4-dicarboxylato
- pic
pyridine-2-carboxylato
- 3-OHpic
3-hydroxypyridine-2-carboxylato
- 3-acetpic
3-acetatoxypyridine-2-carboxylato
- m,n-pdc
pyridine-m,n-dicarboxylato
- ox
oxalato
- pzc
pyrazine-2-carboxylato
- 3-NH2pzc
3-aminopyrazine-2-carboxylato
- 4OH-2,6pdc
4-hydroxy-2,6-pyridinedicarboxylato
- IDA
iminodiacetato
- cit
citrato
- EDTA
ethylenediaminetetraacetato
- HEDTA
ethylene-diaminetetraacetic acid
- isoquin
isoquinoline-2-carboxylato
- quin
quinolato
- NTA
nitrilotriacetato
- glyH
glycine
- cystH
cysteine
- nicH
nicotinic acid
- Hheida
N-(2-hydroxyethyl)iminodiacetato 相似文献
7.
R. R. J. Arroo A. P. M. De Brouwer A. F. Croes G. J. Wullems 《Plant cell reports》1995,15(1-2):133-137
Thiophenes are polyacetylene-related heterocyclic metabolites. Some of these compounds are phototoxic, but the bithiophenes occurring inTagetes mainly accumulate in the root where photo-activation is not likely to occur. A cell-free extract from the fungusFusarium oxysporum induced biosynthesis of hydrophilic thiophenes in root cultures and roots of seedlings ofTagetes patula. The thiophenes formed were partially excreted into the culture medium. The excreted thiophenes inhibited fungal growth in the absence of light and thus may play a role in the biochemical defense against pathogens.Abbreviations BBT
5-(3-buten-1-ynyl)-2,2-bithienyl
- BBTOAc
5-(4-acetoxy-1-butynyl)-2,2-bithienyl
- BBT(OAc)2
5-(3,4-diacetoxy-1-butynyl)-2,2-bithienyl
- BBTOH
5-(4-hydroxy-1-butynyl)-2,2-bithienyl
- BBT(OH)2
5-(3,4-dihydroxy-1-butynyl)-2,2-bithienyl
- HPLC
high-performance liquid chromatography
- UV
ultraviolet 相似文献
8.
J. Fagerberg J-E. Frödin H. Wigzell H. Mellstedt 《Cancer immunology, immunotherapy : CII》1993,37(4):264-270
The antitumor effector functions of unconjugated monoclonal antibodies in cancer therapy are complex. Direct cytotoxic mechanisms such as antibody-dependent cellular cytotoxicity, complement-dependent cytolysis and apoptosis have been suggested. Induction of anti-idiotypic (ab2) and anti-anti-idiotypic (ab3) antibodies as well as T cell (T2 and T3 respectively) responses have also been proposed to be of clinical importance. In this study induction of an immune network cascade in patients with colorectal carcinoma, treated with mAb 17-1A (ab1) was assessed. All patients developed anti-idiotypic antibodies (ab2) of the IgG class after treatment with ab1 and four of nine patients showed induction of mouse Ig reactive T cells [a proliferative response to F(ab)2 fragments of ab1]. Patients with such a T cell response developed anti-anti-idiotypic antibodies (ab3), while those lacking the T cell reactivity failed to mount an ab3 response. Three of four patients with a T cell response achieved a tumor response to mAb therapy. Thus, all responding patients belonged to the group of individuals developing ab3. Induction of mAb(ab1)-reactive T cells as well as an immune network cascade might be important antitumor effector functions of mAb and should be considered in the future design of mAb-based therapy protocols in cancer patients. 相似文献
9.
Assignment of ecto-5′-nucleotidase to human chromosome 6 总被引:2,自引:1,他引:1
Summary Ecto-5-nucleotidase activity (5NT) was measured on whole cells of 26 human x Chinese hamster hybrids. Concordance analysis showed 100% correlation between enzyme activity and inheritance of human chromosome 6. This observation was confirmed by a segregation analysis in which cells of a hybrid containing chromosome 6 were stained by indirect immunofluorescence for HLA Class 1 antigen and sorted by a fluorescence-activated cell sorter (FACS). Cells in the HLA- compartment were cloned and expression of HLA and 5NT was determined. Of nine clones, three were HLA-, 5NT- and six were HLA+, 5NT+, supporting the linkage of 5NT to chromosome 6. 相似文献
10.
Kai Ding Tomas Ekberg Jesper Zeuthen Susann Teneberg Karl-Anders Karlsson Anders Rosén 《Glycoconjugate journal》1993,10(5):395-405
Mice were immunized with a neoglycoprotein consisting of a chemically modified carbohydrate moiety (reductively aminated 3-sialyllactose) linked to human serum albumin. By this procedure an antibody response to the normally non-immunogenic carbohydrate structure was obtained. Hybridomas were established, and monoclonal antibodies were selected in ELISA based on their binding to the saccharide hapten, or to a lactosylceramide-mimicking neoglycolipid, lactose-bis-sulfone. One of the selected antibodies, 2H4, was of particular interest, since it also bound to glycolipids present on melanoma cells. FACS analysis of a panel of 14 melanoma cell lines showed that the 2H4 antibody bound to the majority of these. In frozen, non-fixed sections or paraffin sections of biopsies the monoclonal antibody 2H4 stained melanoma cells, but not tumour infiltrating lymphocytes or normal skin. Detailed immunochemical analysis of 2H4, using thin layer chromatography revealed that it recognized an internal lactose epitope in several glycosphingolipids.Abbreviations BSA
bovine serum albumin
- FACS
fluorescence activated cell sorter
- ELISA
enzyme-linked immunosorbent assay
- HSA
human serum albumin
- LacCer
lactosylceramide
- MAb
monoclonal antibody
- PBS
phosphate buffered saline 相似文献
11.
We demonstrate in this work that HCO
inf3
sup–
uptake in the marine macroalga Ulva sp. features functional resemblances to anion transport mediated by anion exchangers of mammalian cell membranes. The evidence is based on (i) competitive inhibition of photosynthesis by the classical red-blood-cell anion-exchange blockers 4,4-dinitrostilbene-2,2-disulfonate and 4-nitro-4-isothiocyanostilbene-2,2-disulfonate under conditions where HCO
inf3
sup–
, but not CO2, was the inorganic carbon form taken up; (ii) inhibition of HCO
inf3
–
uptake by pyridoxal phospate, indicating the involvement of lysine residues in the binding/translocation of HCO
inf3
sup–
; and (iii) inhibition of HCO
inf3
sup–
(but not of CO2) uptake by exofacial trypsin treatments, indicating the functional involvement of a plasmalemma protein. It is suggested that HCO
inf3
sup–
uptake mediated by such a putative anion transporter can be a fundamental step in providing inorganic carbon for the CO2-concentrating system of marine marcoalgae in an environment where the HCO
inf3
sup–
concentration is high, but the CO2 concentration and rates of uncatalyzed HCO
inf3
sup–
dehydration are low.Abbreviations CI
ionorganic carbon
- DIDS
4,4-diisothiocyanostilbene-2,2-disulfonate
- DNDS
4,4-dinitrostilbene-2,2-disulfonate
- NIDS
4-nitro-4-isothiocyanostilbene-2,2-disulfonate
- PLP
pyridoxal phosphate
- Rubisco
ribulose-1,5-bisphosphate carboxylase-oxygenase 相似文献
12.
Hisanori Suzuki Yasuharu Tanaka Daniela Tornese Buonamassa Benedetta Farina Enzo Leone 《Molecular and cellular biochemistry》1987,74(1):17-20
The effects of analogs of diadenosine 5,5-p1,p4-tetraphosphate (Ap4A) were examined on the ADP-ribosylation reaction of histone Hl catalysed by purified bovine thymus poly(ADP-ribose)transferase. Among the compounds tested, Ap4A and ApCH2PPPA were shown to be the most efficient inhibitors of the enzyme. From kinetic studies of their action, it appears that Ap4A and ApCH2pppA might be mixed type inhibitors.Abbreviations ADP-ribose
adenosine diphosphate ribose
- ADPRT
poly-(ADP-ribose)transferase
- Ap4A
diadenosine 5,5-p1,p4-tertraphosphate
-
Ap4A
diadenosine 5,5-p1,p4(-1,N6-ethenyl-)tetra-phosphate
-
ApAA
diadenosine 5,5-p1,p4(-N6(-1,N6-)bisethenyl-)tetraphosphate
- ApCH2pppA
diadenosine 5,5-p1,p4(-p1,p2-methylene-)tetraphosphate
- AppCH2ppA
diadenosine 5,5-p1,p4(-p2,p3methylene-)tetraphosphate
- AppNHppA
diadenosine 5,5-p1,p4(-p2,p3-amino-)tetraphosphate
- AppCHBrppA
diadenosine 5,5-p1,p4(-p2,p3-bromine methyno-)tetraphosphate
- CpCH2ppCH2PC
dicytidine 5,5-p1,p4(-p1,p2-p3,p4-bismethylene-)tetraphosphate
- ApCH2ppCH2pA
diadenosine 5,5-p1,p4(-p1,p2-p3,p4-bismethylene-)tetraphosphate. 相似文献
13.
Hiroaki Sawai 《Journal of molecular evolution》1981,17(1):48-51
Summary Oligouridylates with more than eight chain units can serve as a template for the template-directed condensation of ImpA catalyzed by Pb2+ ion. The templates and the Pb2+ ion catalyst facilitate the formation of longer oligoadenylates with five or more units. The ratio of 3–5 linked oligomers to the 2–5 isomers increases with increasing chain length of the oligouridylate template. Short oligouridylates up to a hexamer tend to decrease the yield of oligoadenylates, and do not affect the selectivity of internucleotide linkage.Abbreviations EDTA
ethylenediaminetetracetic acid
- Tris
tris(hydroxymethyl)aminomethane
- A
adenosine
- ImpA
adenosine 5-phosphorimidazolide
- pA
adenosine 5-phosphate
- Ap
adenosine 2(3)-phosphate
- poly A
polyadenylic acid
- AppA
P1,P2-diadenosine 5-diphosphate
- pAp
adenosine 2(3),5-diphosphate
- ApA
adenylyl adenosine
- (pA)n (n = 2,3,)
oligomers of pA
- ImpApA
5-phosphorimidazolide of ApA
- U
uridine
- pU
uridine 5-phosphate
- Up
uridine 2(3)-phosphate
- poly U
polyuridylic acid
- pUp
uridine 2(3),5-diphosphate
- (pU)n (n = 2,3,)
oligomers of pU
- (pU)n – (pA)m
cooligomers composed of (pU)n and (pA)m units
- AppUpUpUpUp
pyrophosphate derived from pA and (pU)4
- AppUp
P1-(adenosine 5)-P2-(uridine 2(3)-phosphate 5) -pyrophosphate
- BAP
bacterial alkaline phosphatase
- VPD
venom phosphodiesterase
- N.P1
nuclease P1
- RNase A
pancreatic ribonuclease
- A*
radioactive adenosine 相似文献
14.
Tritiated 9-nor-fusicoccin-8-alcohol provides a highly bioactive radioligand of high specific activity which is easily prepared by oxidation of fusicoccin and subsequent reduction with tritiated sodium borohydride. Using this radioligand, we have identified and characterized a selective binding site for fusicoccin (Ka for [3H]-9-nor-fusicoccin-8-alcohol=0.20·109 M-1; Ka, apparent for fusicoccin=0.21·109 M-1) located at the plasmalemma of Vicia faba leaf tissue. The site is thermolabile, readily degraded by trypsin and located at the apoplastic face of the plasmalemma based on results obtained using right-side-out plasmalemma vesicles prepared by aqueous two-phase partitioning and macromolecular fusicoccin-derivatives. The binding-protein is present in guard cells of Vicia faba, as shown by the use of purified guard-cell protoplasts.Abbreviations BSA
bovine serum albumin
- DTT
dithiothreitol
- EDTA
ethylenediaminetetraacetate
- FC
fusicoccin
- FCol
9-nor-fusicoccin-8-alcohol
- Mes
2(N-morpholino)ethanesulfonic acid
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol 相似文献
15.
Summary Unlike wild-type Saccharomyces cerevisiae, yeast cells carrying the tup7 mutation are able to take up exogenously-supplied dTMP. The tup7 mutant was also found to be dramatically sensitive to growth inhibition by FdUMP and BrdUMP. The exclusive mode of action of FdUMP in such strains was shown to be inhibition of thymidylate synthetase. Spontaneously-arising derivatives resistant to FdUMP and BrdUMP were isolated from the tup7 strain. Genetically, these mutations were recessive and defined three complementation groups (fdr1, fdr2, and bdr2), unlinked to the tup7 locus and to each other. No resistance mutations were obtained which mapped at the structural gene for thymidylate synthetase. Biochemical analysis of cells carrying these mutations showed that in the case of fdr2 and bdr2, in addition to an inability to transport dTMP, acid and alkaline phosphatase levels were affected, indicating that phosphatase expression and 5-mononucleotide permeability are coordinately controlled. In contrast, the fdr1 mutation and a previously identified suppressor of dTMP-permeability, sot1, affected only 5-mononucleotide uptake and may define components of the permease responsible for dTMP entry.List of Abbreviations BrdUMP
5-bromo-2-deoxyuridine-5-monophosphate
- ddH2O
deionized distilled water
- FdUMP
5-fluoro-2-deoxyuridine-5-monophosphate
- PMSF
phenylmethyl-sulfonylfluoride
- TEOLA
2,2,2-nitrilotriethanol (triethanolamine)
- Tris
tris(hydroxymethyl)aminomethane 相似文献
16.
Joseph M. Wu Stanley J. Wertheimer Behruz Eslami Joanne C. Figuereido Biswendu B. Goswami 《Bioscience reports》1985,5(12):1041-1051
Rabbit reticulocyte lysates, gel filtered on Sephadex G-25 with or without ATP (or its analogs), were preincubated at 37°C and their subsequent binding to p3A4,3-[32P]pCp was studied. Lysates filtered without ATP or in the presence of 0.1 mM 8-bromo-ATP, 1,N6-etheno-ATP, or ITP showed a time-dependent decrease in binding activity. This decrease was completely prevented when lysates were filtered with 0.1 mM ATP, 2-deoxy-ATP, --methylene-ATP, or ATP--S. The stability of binding provided by ATP or 2-deoxy-ATP analogs corresponds to a more active 2–5A dependent endonucleolytic (RNAase L) activity based on studies using [3H] viral mRNA. Chromatography on heparin-agarose showed that ATP-supplemented gel-filtered reticulocyte lysates had a different p3A4,3-[32P]pCp binding activity elution-profile than lysates gel-filtered in the absence of ATP. Covalent cross-linking of periodate-oxidized p3A4,3-[32P]pC to gelfiltered lysates, preincubated at 0°C or 37°C for 30 min, showed the following results: (1) all lysates gave a major cross-linking of the radioactive ligand to an 80 000 dalton polypeptide, regardless of the temperature of preincubation, (2) Iysates gel-filtered without ATP, with 0.1 mM ITP, or --methylene-ATP, showed a significant reduction in the cross-linking of the 80 000 dalton protein, after preincubation at 37°C for 30 min. This decrease was accompanied by an increase in the labeling of two smaller polypeptides.Abbreviations used 2 5-oligoadenylates
oligonucleotides consisting of 5-adenylic acid residues joined by a 2 5-phosphodiester linkage 相似文献
17.
Hiroaki Sawai 《Journal of molecular evolution》1988,27(3):181-186
Summary Polymerization of various nucleoside-5-phosphorimidazolides has been conducted in neutral aqueous solution using divalent metal ions as catalysts. Oligonucleotide formation took place from each of the ribonucleoside-5-phosphorimidazolides, ImpC, ImpU, ImpA, ImpG, and ImpI. The yields and distributions of the resulting oligonucleotides varied depending on the difference of the nucleic acid base and the metal ions used. The catalytic effect of divalent metal ions on the formation of oligocytidylates occurred in the following order: Pb2+>Zn2+>Co2+, Mn2+>Cd2+>Cu2+>Ni2+>Ca2+, Mg2+, none >Hg2+. The order changes slightly for other types of oligoribonucleotide formation. Oligoribonucleotides up to hexamers were obtained in 35–55% overall yield, when Pb2+ ion was used as a catalyst. Zn2+ ions yielded oligoribonucleotides up to tetramers in 10–20% overall yield. The resulting oligonucleotides contained mainly 2–5 internucleotide linkages.Little or no oligonucleotide was obtained from nucleoside-5-phosphorimidazolides modified in the sugars, Imp(3-dA), Imp(2-dA), Imp(Ara), Imp(Aris), and Imp(Nep). The results indicate that a ribosyl system is required for the metal ion-catalyzed synthesis of oligonucleotides.
Abbreviations. EDTA, ethylenediaminetetraacetic acid; Versenol,N-hydroxyethylethylenediaminetriacetic acid; Tris, tris-(hydroxymethyl)aminomethane; pN (N is A, C, G, U, I, 3-dA, 2-dA, AraA, Aris, or Nep), nucleoside-5-phosphate; Np, nucleoside-2(3)-phosphate; I, inosine; 3-dA, 3-deoxyadenosine; 2-dA, 2-deoxyadenosine; AraA, arabinosyladenine; Aris, aristeromycin; Nep, neplanocin A; ImpN, nucleoside-5-phosphorimidazolide; NppN, P1,P2-dinucleoside-5,5-pyrophosphate; (pN)n (n=2, 3, ...), oligomers of pN, numbers given between a nucleoside and a phosphate indicate the type of internucleotide linkage, e.g., pC2 p5C is 5-phosphorylcytidyl-(2–5)-cytidine;
, cyclic dimers of pN; BAP, bacterial alkaline phosphatase; N.Pl, nuclease Pl; VPDase, venom phosphodiesterase; HPLC, high pressure liquid chromatography 相似文献
18.
Desulfobacter postgatei grows on acetate and sulfate as energy source. The oxidation of acetate to 2 CO2 proceeds via the citric acid cycle involving membrane-bound succinate dehydrogenase and membrane-bound malate dehydrogenase. We report here that the organism contains membrane-bound NADPH dehydrogenase and ferredoxin: NADP oxidoreductase for the reoxidation of NADPH and reduced ferredoxin generated during isocitrate- and 2-oxoglutarate oxidation, respectively. The presence of proton translocating ATPase activity is also described.NADPH dehydrogenase and succinate dehydrogenase were found to be electrically connected within the membrane and electron transfer between these two enzymes was shown to be coupled with proton translocation. The membrane fraction catalyzed the oxidation of NADPH with fumarate and the reduction of NADP with succinate. NADPH oxidation with fumarate was stimulated by protonophores and inhibited by the proton translocating ATPase inhibitor dicyclohexylcarbodiimide (DCCD) and by heptylhydroxyquinoline-N-oxide (HQNO); inhibition by DCCD was relieved by protonophores. NADP reduction with succinate was dependent on ATP and inhibited by protonophores, DCCD, and HQNO. The membrane fraction also mediated the oxidation of NADPH with the water soluble menaquinone analogue dimethylnaphthoquinone (DMN) and the reduction of fumarate with DMNH2. Only the former reaction was stimulated by protonophores and only the latter reaction was inhibited by HQNO. This suggests that the NADPH dehydrogenase reaction is the site of energy conservation and the succinate dehydrogenase is the site of HQNO inhibition.Non-standard abbreviations APS
Adenosine 5-phosphosulfate
- DCCD
N,N-dicyclohexylcarbodiimide
- DCPIP
2,6-dichloroindophenol
- DMN
2,3-dimethyl-1,4-naphthoquinone
- DTT
DL-1,4-dithiothreitol
- HQNO
2(n-heptyl)-4-hydroxyquinoline-N-oxide
- TCS
3,5,3,4-tetrachlorosalicylanilide
- Tricine
N-tris-(hydroxymethyl)methylglycine
- TTFB
4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole
- SF-6847
3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile 相似文献
19.
Peng Yuan Vincent P. Marshall Gary L. Petzold Roger A. Poorman Brian J. Stockman 《Journal of biomolecular NMR》1999,15(1):55-64
This report describes the backbone amide dynamics of the uniformly 15N labeled catalytic domain of human stromelysin complexed to PNU-99533, a hydroxamate-containing ligand that binds to the S1-S3 region (right side) of the stromelysin active site, and to PNU-107859 and PNU-142372, both thiadiazole-containing ligands that bind to the S1-S3 region (left side) of the stromelysin active site. 15N R1, R2 and NOE NMR relaxation measurements were recorded and analyzed for each complex. Different dynamic behaviors were observed for stromelysin complexed to the two classes of ligands, indicating that it may be possible to use protein dynamics to distinguish between different binding orientations. In the absence of bound ligand at the S1-S3 subsites, the S1-S3 residues were found to be relatively rigid. In contrast, the S1-S3 subsites were found to be flexible in the absence of interactions with ligand. The relative rigidness of the S1-S3 subsites may be responsible for MMP binding specificity by discriminating between ligands of different shapes. By contrast, the inherent flexibility of the S1-S3 subsites allows structural rearrangement to accommodate a broad range of incoming substrates or inhibitors. Similarities and differences in dynamics observed for each complex provide insights into the interactions responsible for protein–ligand recognition. The relevance of protein dynamics to structure-based drug design is discussed. 相似文献
20.
L. Renwrantz W. Schmalmack R. Redel B. Friebel H. Schneeweiß 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,165(8):647-658
Haemocytes oxidized 3-amino-9-ethylcarbazole and other peroxidase indicators such as 3,3-diaminobenzidine·4HCl, 3,3,5,5 tetramethylbenzidine·2HCl and 4-chloro-1-naphthol without addition of H2O2 indicating that the reaction was possibly not caused by a peroxidase. As these chromogens were also converted by a mushroom phenoloxidase in the absence of H2O2, cell smears were incubated with known substrates of phenoloxidases. One of these, l-dopa, caused strong melanin formation in several haemocytes and the reaction could be blocked by a variety of inhibitors including KCN, NaF, 1-phenyl-2-thiourea, cysteine, glutathione, ascorbic acid and HgCl2. The enzymatic activity was isolated using a concanavalin A column and separated into two fractions with an ion-exchange cartridge. The molecular weights of the glycoproteins were estimated to be 381±13.7 kDa and 316±11.1 kDa. After isoelectric focusing of a haemocyte extract and the two ion-exchange peaks, seven enzyme bands were detected with isoelectric points between pH 5.0 and 5.5. The isolated enzyme fractions both converted 3,3,5,5-tetramethylbenzidine·2HCl best at pH 5–6 and l-dopa at pH 7.0 without addition of H2O2. Heat-treated cells lost their enzymatic activity; however, a group of haemocytes still bound preoxidized 3-amino-9-ethylcarbazole (= AECox). Also, some of the phenoloxidase inhibitors mentioned above blocked this non-enzymatic staining reaction. About 30–57% of haemocytes from individual mussels were AECox-positive, whereas Mytilus specimens without phenoloxidase-containing cells often occurred. Haemocytes containing this enzyme exhibited a high mobility and a large percentage of them belonged to a cytotoxic cell population.Abbreviations
AEC
3-amino-9-ethylcarbazole
-
AECox
preoxidized AEC
-
BSA
bovine serum albumin
-
4CN
4-chloro-1-naphthol
-
DAB
3,3-diaminobenzidine·4HCl
-
DMFA
dimethylformamide
-
EDTA
ethylenediaminetetra-acetic acid
-
LGT
Iow gelling temperature
-
MW
molecular weight
-
PAGE
polyacrylamide gel electrophoresis
-
PMSF
phenylmethylsulphonylfluoride
-
PTU
1-phenyl-2-thiourea
-
RBC
red blood cells
-
TCA
trichloroacetic acid
-
TMB
3,3,5,5-tetramethylbenzidine·2 HCl 相似文献