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311.
Dynamics of centromere and kinetochore proteins; implications for checkpoint signaling and silencing
Shah JV Botvinick E Bonday Z Furnari F Berns M Cleveland DW 《Current biology : CB》2004,14(11):942-952
BACKGROUND: The mitotic checkpoint prevents the onset of anaphase before all chromosomes are attached to spindle microtubules. The checkpoint is thought to act by the catalytic generation at unattached kinetochores of a diffusible "wait signal" that prevents anaphase. Mad2 and Cdc20, two candidate proteins for components of a diffusible wait signal, have previously been shown to be recruited to and rapidly released from unattached kinetochores. RESULTS: Fluorescence recovery after photobleaching demonstrated that Mad1, Bub1, and a portion of Mad2, all essential mitotic-checkpoint components, are stably bound elements of unattached kinetochores (as are structural centromere components such as Centromere protein C [CENP-C]). After microtubule attachment, Mad1 and Mad2 are released from kinetochores and relocalize to spindle poles, whereas Bub1 remains at kinetochores. CONCLUSIONS: A long residence time at kinetochores identifies Bub1, Mad1, and a portion of Mad2 as part of a catalytic platform that recruits, activates, and releases a diffusible wait signal that is partly composed of the rapidly exchanging portion of Mad2. The release of Mad1 and Mad2, but not Bub1, from kinetochores upon attachment separates the elements of this "catalytic platform" and thereby silences generation of the anaphase inhibitor despite continued rapid cycling of Mad2 at spindle poles. 相似文献
312.
Sustained activation of JNK/p38 MAPK pathways in response to cisplatin leads to Fas ligand induction and cell death in ovarian carcinoma cells 总被引:28,自引:0,他引:28
Mansouri A Ridgway LD Korapati AL Zhang Q Tian L Wang Y Siddik ZH Mills GB Claret FX 《The Journal of biological chemistry》2003,278(21):19245-19256
313.
Mahmood-Ul-Hassan Chohan ZH Scozzafava A Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2004,19(3):263-267
Schiff's bases were obtained from aromatic/heterocyclic sulfonamides and amino-sulfonamide derivatives, such as sulfanilamide, homosulfanilamide, 4-aminoethyl-benzenesulfonamide and 5-amino-1,3,4-thiadiazole-2-sulfonamide. Metal complexes of some of these Schiff's bases, incorporating Zn(II), Co(lI), Ni(II) and Cu(II) ions, were also prepared and tested as inhibitors of the zinc enzyme carbonic anhydrase (CA), and more specifically the red blood cell isozymes I and II. The Schiff's bases behaved as medium potency CA I and CA II inhibitors, whereas their metal complexes showed a highly enhanced potency, with several low nanomolar CA II inhibitors detected. 相似文献
314.
Khan KM Saify ZS Khan MZ Zia-Ullah Choudhary IM Atta-Ur-Rahman Perveen S Chohan ZH Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2004,19(4):373-379
The synthesis and selective biological screening of 7-hydroxy-4-methyl-2H-chromen-2-one (2), 7-hydroxy-4,5-dimethyl-2H-chromen-2-one (15) and some of their derivatives were carried out. Compound 13 was found to be most potent cytotoxic agent with LD50 = 126.69 microg/ml. In antibacterial assay the compounds showed a broad spectrum of activities. Compound 11 exhibited a very high degree of plant growth inhibition at three levels of concentration. Compound 4 showed very promising antifungal activity against Candida albicans. Compounds 12 and 13 demonstrated excellent antioxidant activity. 相似文献
315.
Khan KM Iqbal S Lodhi MA Maharvi GM Perveen S Choudhary MI Atta-Ur-Rahman Chohan ZH Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2004,19(4):367-371
Dicoumarols 1-10 with substituted phenyl residues at C-11 were synthesized and screened for their urease inhibition effects. All synthesized compounds showed varying degree of urease inhibitory activity ranging from IC50 = 74.30-91.35 microM. 相似文献
316.
Chohan ZH Rau A Noreen S Scozzafava A Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2002,17(2):101-106
Nicotinic acid derived Schiff bases and their transition metal [cobalt(II), nickel(II) and zinc(II)] complexes have been prepared and characterized by physical, spectral and analytical data. The Schiff bases act as deprotonated tridentate ligands for the complexation of the above mentioned metal ions. These complexes, possessing the general formula [M(L)2] [where M = Co(II), Ni(II) and Zn(II) and L = HL1-HL4] showed an octahedral geometry of the metal ions. For determining the effect of metal ions upon chelation, the Schiff bases and their complexes have been screened for antibacterial activity against several pathogenic strains of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The new metal derivatives reported here were more bactericidal against one or more bacterial species as compared to the uncomplexed Schiff bases. 相似文献
317.
Ribosomal protein L16 was digested with Staphylococcus aureus protease V8 and the resulting peptides were separated by reversed-phase high-performance liquid chromatography. One of the fragments, identified by sequence analysis as the N-terminal peptide of L16, was shown to exhibit partial peptide-bond-formation and transesterification activities of peptidyltransferase upon reconstitution with L16-depleted 50S core particles. However, several proteins enhanced these activities. L15 increased both reactions when added to the reconstitution mixture, suggesting a limited capacity of the L16 peptide to incorporate into 50S core particles. In contrast, the interaction of L11 with the N-terminal peptide stimulated the transesterification reaction but not the peptide-bond-forming activity of ribosomes, indicating a different topological domain for these reactions. Also, EF-P, a soluble protein which reconstructs the peptide-bond formation and transesterification reactions on 70S ribosomes, stimulated both peptidyltransferase activities exhibited by the L16 N-terminal peptide. 相似文献
318.
Mozaffar Zahid Nakanishi Kazuhiro Matsuno Ryuichi 《Applied microbiology and biotechnology》1989,31(1):59-60
Summary Free amino groups of -galactosidase-1-from Bacillus circulans were partially modified using different glutaraldehyde concentrations to increase trisaccharide production from lactose. Glutaraldehyde of 0.01%–0.03% modified 15%–40% of the free amino groups of the enzyme. The maximum yield of trisaccharide increased from 6% to 12% depending upon the degree of modification with 25% conversion of 127 mM lactose. Modification of 50% of the free amino groups of the enzyme using 0.05% glutaraldehyde produced a considerable amount of tetrasaccharide along with trisaccharide even at the initial stage of the reaction. 相似文献
319.
320.