• Title/Summary/Keyword: Biological Synthesis

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Functional Analysis of the Invariant Residue G791 of Escherichia coli 16S rRNA

  • Song, Woo-Seok;Kim, Hong-Man;Kim, Jae-Hong;Sim, Se-Hoon;Ryou, Sang-Mi;Kim, Sang-Goo;Cha, Chang-Jun;Cunningham, Philip R.;Bae, Jee-Hyeon;Lee, Kang-Seok
    • Journal of Microbiology
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    • v.45 no.5
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    • pp.418-421
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    • 2007
  • The nucleotide at position 791(G791) of E. coli 16S rRNA was previously identified as an invariant residue for ribosomal function. In order to characterize the functional role of G791, base substitutions were introduced at this position, and mutant ribosomes were analyzed with regard to their protein synthesis ability, via the use of a specialized ribosome system. These ribosomal RNA mutations attenuated the ability of ribosomes to conduct protein synthesis by more than 65%. A transition mutation (G to A) exerted a moderate effect on ribosomal function, whereas a transversion mutation (G to C or U) resulted in a loss of protein synthesis ability of more than 90%. The sucrose gradient profiles of ribosomes and primer extension analysis showed that the loss of protein-synthesis ability of mutant ribosomes harboring a base substitution from G to U at position 791 stems partially from its inability to form 70S ribosomes. These findings show the involvement of the nucleotide at position 791 in the association of ribosomal subunits and protein synthesis steps after 70S formation, as well as the possibility of using 16S rRNA mutated at position 791 for the selection of second-site revertants in order to identify ligands that interact with G791 in protein synthesis.

Synthesis and Biological Evaluation of 1-Heteroarylmethyl 1,4-Diazepanes Derivatives as Potential T-type Calcium Channel Blockers

  • Ullapu, Punna Reddy;Ku, Su-Jin;Choi, Yeon-Hee;Park, Ji-Yeon;Han, So-Yeop;Baek, Du-Jong;Lee, Jae-Kyun;Pae, Ae-Nim;Min, Sun-Joon;Cho, Yong-Seo
    • Bulletin of the Korean Chemical Society
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    • v.32 no.spc8
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    • pp.3063-3073
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    • 2011
  • The synthesis and biological evaluation of 1-heteroarylmethyl 1,4-diazepane derivatives as potential T-type calcium channel blockers is described. In this study, we have identified the compound 21i exhibiting the most potent T-type calcium channel blocking activity with $IC_{50}$ value of 0.20 ${\mu}M$, which is superior to that of mibefradil.

Synthesis, Characterization, Luminescence and Biological Activity of Two Lanthanide Complexes Involving Mixed Ligands

  • Ma, De-Yun;Guo, Hai-Fu;Qin, Liang;Xu, Jun
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2774-2780
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    • 2013
  • Two new isostructural dinuclear complexes, $Ln_2(4-cpa)_6(bpy)_2$ (Ln = Eu (1); Tb (2), 4-cpa = 4-chlorophenylacetate, bpy = 2,2'-bipyridine), have been hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction and single-crystal X-ray diffraction. The lanthanide ions are bridged by two bidentate and two terdentate carboxylate groups to give centrosymmetric dimers with $Ln{\cdots}Ln$ separations of 3.967(2) and 3.956(3) ${\AA}$, respectively. Each metal atom is nine-coordinate and exhibits a distorted tricapped trigonal prismatic geometry. Three-dimensional fluorescence spectra show that both 1 and 2 emit bright red and green luminescence at room temperature, with long lifetimes of up to 0.369 ms (at 614 nm) and 0.432 ms (at 543 nm), respectively. Moreover, poor luminescence efficiency has been noted for complex 2. The 4-Hcpa ligand and complexes 1-2 have been screened for their phytogrowth-inhibitory activities against Brassica napus L. and Echinochloa crusgalli L., and the results are compared with the activity of quizalofop-P-ethyl.

Chemical Synthesis and Determination of Biological Activity of the Epidermal Growth Factor-Like Domain of Mouse Betacellulin

  • Shin, Song-Yub;Kang, Shin-Won;Ha, Jong-Myung
    • BMB Reports
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    • v.28 no.2
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    • pp.87-93
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    • 1995
  • To investigate the biological functions of the EGF-like domain of mouse betacellulin (BTC), mouse BTC(33-80), a 48-residue peptide corresponding to the EGF-like domain, was synthesized by stepwise solidphase methods using a 9-fluorenylmethoxycarbonyl (Fmoc) strategy. The homogeneity of synthetic mouse BTC(33-80) was confirmed by analytical reversed phase (RP)-HPLC, amimo acid analysis, and fast atom bombardment mass spectrometer (FAB-MS). Three disulfide bond pairings of synthetic mouse BTC(33-80) were established by amino acid analysis of cysteine-containing fragments derived from thermolytic digestion. These were consistent with the pairings of EGF and transforming growth factor ($TGF-{\alpha}$). The EGF-Iike domain of mouse BTC showed equipotent activity in both EGF-receptor binding on A-431 epidermoid carcinoma cells, and mitogenesis on NIH-3T3 fibroblast cells, as compared with authentic h-EGF. Results suggest that the EGF-Iike domain of BTC plays a significant role in mitogenic activity with an EGF-receptor mediated system.

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Cytokines and Depression (사이토카인과 우울증)

  • Kim, Yong-Ku
    • Korean Journal of Biological Psychiatry
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    • v.15 no.3
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    • pp.175-185
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    • 2008
  • Accumulating evidence has suggested the existence of reciprocal communication between immune, endocrine, and neurotransmitter system. Cytokine hypothesis of depression implies that increased pro-inflammatory cytokine such as -1, IL-6, IL-12, TNF-${\alpha}$, and IFN-${\gamma}$ in major depression, acting neuromodulators, play a key role in the mediation of behavioral, neuroendocrine, and neurochemical disturbances in depression. Concerning the relation between cytokines and serotonin metabolism, pro-inflammatory cytokines have profound effects on the metabolism of brain serotonin through the enzyme indoleamine-2,3-dioxygenase(IDO) that metabolizes tryptophan, the precursor of 5-HT to neurodegenerative quinolinate and neuroprotective kynurenate. The neurodegeneration process is reinforced by the neurotoxic effect of the hypercortisolemia during depression. From this perspective, it is possible that efficacy of antidepressants in the treatment of depression may, at least in part, rely on downregulation of pro-inflammatory cytokine synthesis. So, the use of cytokine synthesis inhibitors or cytokine antagonists may be a new treatment approach in depression. However, at present the question whether cytokines play a causal role in the onset of depression or are mere epiphenomena sustaining depressive symptoms remains to be elucidated. Nevertheless, cytokine hypothesis has created new perspectives in the study of psychological and pathophysiological mechanism that are associated with major depression, as well as the prospect for developing a new generation antidepressants.

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Synthesis of Methyl 3-methyloctanoate, the Key Perfume Component of African Orchid Aerangis confusa (아프리카 난 Aerangis confusa의 향기성분 methyl 3-methyloctanoate의 합성)

  • Kim, Hyun-Ok;Kim, Young-Ju;Kim, Bieong-Kil;Seu, Young-Bae
    • Applied Biological Chemistry
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    • v.48 no.3
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    • pp.292-295
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    • 2005
  • Synthesis of methyl 3-methyloctanoate, a perfume component isolated from African orchid Aerangis confusa (or Aerangis kirkii) was achieved starting from itaconic acid in 9 steps. Itaconic acid is one of the cheapest organic compounds which is the fermentation product of microorganism Asp. terreus. As the key intermediate, 2-methyl-1,4-butanediol 4-acetate was obtained through the enzymatic regioselective hydrolysis of 2-methyl-1,4-butanediol diacetate with lipase. After Grignard reaction and oxidation, 3-methyloctanoic acid was obtained and converted to the various corresponding scented esters with a variety of alkyl alcohols, and the resulting fragrancy esters are expected to be utilized as the aroma additive materials in cosmetics, drinks and foods.

Spirodiclofen Analogues as Potential Lipid Biosynthesis Inhibitors: A Convenient Synthesis, Biological Evaluation, and Structure-Activity Relationship

  • Ke, Shaoyong;Sun, Tingting;Zhang, Zhigang;Zhang, Ya-Ni;Liang, Ying;Wang, Kaimei;Yang, Ziwen
    • Bulletin of the Korean Chemical Society
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    • v.31 no.8
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    • pp.2315-2321
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    • 2010
  • Twenty spirodiclofen analogues have been designed and conveniently synthesized via three steps including esterification, one-pot heterocyclization, and acylation reactions. The target molecules have been identified on the basis of analytical spectra ($^1H$ NMR, $^{13}C$ NMR and ESI-MS) data. All newly synthesized compounds have been screened for their potential insecticidal and herbicidal activity by standard method. The preliminary assays indicated that some of analogues displayed moderate to good insecticidal activity against Plutella xylostella compared with spirodiclofen, and some compounds showed obvious activity against Brassica chinensis. Structure-activity relationship (SAR) is also discussed based on the experimental data.

Facile Synthetic Route to Ascorbic Acid-Dipeptide Conjugate via N-Terminal Activation of Peptide on Resin Support

  • Yang, Jin-Kyoung;Kwak, Seon-Yeong;Jeon, Su-Ji;Kim, Hye-In;Kim, Jong-Ho;Lee, Yoon-Sik
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2381-2384
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    • 2014
  • A solid-phase synthetic approach is reported for the synthesis of an ascorbic acid (ASA)-dipeptide conjugate that exhibited enhanced antioxidant activity. The N-terminal amino group of dipeptide (Ala-Ala) on a resin support was first activated by 1,1'-carbonyldiimidazole (CDI), and then reacted with an ASA derivative. The addition of a base, triethylamine (TEA), promoted nucleophilic acylation of ASA derivative and yielded a desired product (ASA-Ala-Ala) with enhanced purity, when cleaved from the resin. Compared to the approach where a C3 hydroxyl group of ASA was first activated with CDI and then reacted with the amino group of dipeptide on the resin, this new approach allowed a significant reduction of a total reaction time from 120 h to 8 h at $25^{\circ}C$. As-prepared ASA-dipeptide conjugate (ASA-Ala-Ala) showed improved antioxidant activity compared to ASA.