• Title, Summary, Keyword: inhibitor binding

Search Result 455, Processing Time 0.039 seconds

A New Cyclophilin Inhibitor from Ganoderma lucidum: Purification and Characterization

  • Lim, Jin-Ik;Jeong, Ki-Chul;Kang, In-Sug;Kim, Soo-Ja
    • Bulletin of the Korean Chemical Society
    • /
    • v.25 no.7
    • /
    • pp.1055-1060
    • /
    • 2004
  • A new inhibitor for peptidylprolyl cis-trans isomerase (PPIase) has been isolated from Ganoderma lucidum and purified to homogeneous state by organic solvent extraction. The purified PPIase inhibitor (GPI) is assumed to be a membrane-associated glycoprotein. GPI inhibits specifically the bovine brain PPIase, a cyclophilin, and has no effect on the FKBP activity. The results of our chemical modification study of GPI indicate the presence of Lys residue(s) at or near its binding site. Like CsA-cyclophilin complex, GPI-bovine brain PPIase complex strongly inhibits the calcineurin activity in vitro, suggesting the possible involvement of GPI in immunomodulating pathway by the formation of PPIase-inhibitor-calcineurin complex.

Chemotactic Effect of Leukotactin-1/CCL15 on Human Neutrophils

  • Lee Ji-Sook;Yang Eun-Ju;Ryang Yong-Suk;Kim In-Sik
    • Biomedical Science Letters
    • /
    • v.12 no.3
    • /
    • pp.145-151
    • /
    • 2006
  • Leukotactin-l (Lkn-l )/CCL15 has been known as a potent chemoattractant of leukocytes. However, the precise function of Lkn-l in human neutrophils has not been explained well. In the present study, we investigated the contribution of Lkn-1 in chemotactic activity of human neutrophils. Both CCR1 and CCR3 mRNA expressions are strongly expressed in human neutrophils but CCR2 protein expression was uniquely detected on the cell surface. Lkn-l binding to CCR1 and CCR3 induced chemotactic activity of neutrophils. Chemotactic index of Lkn-l was comparable to that of IL-8. $MIP-1{\alpha}/CCL3$ binding to CCR1 and CCR5 has no effect on neutrophil migration. Cell migration, in response to Lkn-l, was blocked by pertussis toxin (Ptx), a $G_o/G_i$ protein inhibitor, and U73122, a phospholipase C(PLC) inhibitor but not by protein kinase C inhibitor such as rottlerin, and Ro-31-8425. Taken together, our results demonstrate that Lkn-l transduces the chemotaxis signal through $G_o/G_i$ protein and PLC. This finding provides the molecular mechanism by which Lkn-l may contribute to neutrophil movement into the site of inflammation.

  • PDF

Isovitexin, a Potential Candidate Inhibitor of Sortase A of Staphylococcus aureus USA300

  • Mu, Dan;Xiang, Hua;Dong, Haisi;Wang, Dacheng;Wang, Tiedong
    • Journal of Microbiology and Biotechnology
    • /
    • v.28 no.9
    • /
    • pp.1426-1432
    • /
    • 2018
  • Staphylococcus aureus causes a broad variety of diseases. The spread of multidrug-resistant S. aureus highlights the need to develop new ways to combat S. aureus infections. Sortase A (SrtA) can anchor proteins containing LPXTG binding motifs to the bacteria surface and plays a key role in S. aureus infections, making it a promising antivirulence target. In the present study, we used a SrtA activity inhibition assay to discover that isovitexin, a Chinese herbal product, can inhibit SrtA activity with an $IC_{50}$ of $28.98{\mu}g/ml$. Using a fibrinogen-binding assay and a biofilm formation assay, we indirectly proved the SrtA inhibitory activity of isovitexin. Additionally, isovitexin treatment decreased the amount of staphylococcal protein A (SpA) on the surface of the cells. These data suggest that isovitexin has the potential to be an anti-infective drug against S. aureus via the inhibition of sortase activity.

Competitive Inhibition of Pepsin by Carboxylic Acids (脂肪酸에 依한 Pepsin의 競走的 억제)

  • Hong Dae Shin
    • Journal of the Korean Chemical Society
    • /
    • v.14 no.2
    • /
    • pp.161-168
    • /
    • 1970
  • In order to obtain the more effective evidence, supporting the hypothesis which have been previously described by former report that pepsin (EC 3.4. 4.1) forms a hydrophobic bond with the nonpolar side chain of its substrate, the inhibitory effect of carboxylic acids(from formic acid to iso-butyric acid) on the activity of pepsin to the synthetic dipeptide, N-Carbobenzoxy-L-glutamyl-L-tyrosine, was discussed. The kinetic study showed that the inhibition by carboxylic acids was competitive. The Kidecreased with increasing size of the inhibitor molecule. The $-{\Delta}F^{\circ}$increased linearly with increasing number of carbon atoms in the hydrocarbon chain of the inhibitor. It was confirmed that the hydrophobic bond between more than one side chain of amino acid residues(phenylalanine) in the binding region of the active center of pepsin and the side chain of amino acid residues in the substrate was formed as the first step of its enzymic mechanism. The inhibitory effect of carboxylic acids was due to the competition of the hydrocarbon group of the carboxylic acids with the side chain of the substrate for the hydrophobic binding site(the side chain of phenylalanine) of the pepsin.

  • PDF

A Docking Study of UDP-N-Acetylglucosamine Enolpyruvyl Transferase from Haemophilus influenzae in Complex with Inhibitors

  • Yoon, Hye-Jin;Mikami, Bunzo;Park, Hyun-Ju;Yoo, Ja-Kyung;Suh, Se-Won
    • Korean Journal of Crystallography
    • /
    • v.18 no.1_2
    • /
    • pp.10-15
    • /
    • 2007
  • UDP-N-acetylglucosamine enolpyruvyl transferase (MurA; EC 2.5.1.7) catalyzes the first committed step of peptidoglycan biosynthesis in bacteria, i.e., transfer of enolpyruvate from phosphoenolpyruvate to UDP-N-acetyl-glucosamine. Because the crystallization condition contained a high concentration of ammonium sulfate, our inhibitor binding studies were not successful. Therefore, we employed a docking approach to investigate the inhibitor binding. Our results will be useful in structure-based design of specific inhibitors of MurA for antibacterial discovery.

Identification of the IL-1$\beta$ inhibitor in the febrile patient urine by anti-IL-1$\beta$ monoclonal antibody (Anti-IL-1$\beta$ 단일클론 항체를 이용해서 발열환자의 뇨중 IL-1$\beta$ inhibitor의 확인)

  • 남경수;배윤수;남명수;오은숙;박순희;최인성;정태화
    • YAKHAK HOEJI
    • /
    • v.37 no.4
    • /
    • pp.420-426
    • /
    • 1993
  • To effectively purify of IL-1 inhibitor from human febrile urine, we have established monoclonal antibody that reacts with human recombinant interleukin l$\beta$(IL-1$\beta$). The antibody, designated ON-1, was highly specific to IL-1$\beta$ and no cross-reaction with other cytokines(IL-l$\alpha$ and IL-4) was observed. As the results of ELISA inhibition assay and Western blotting method, it was further identified that ON-1 had high binding specificity with IL-1$\beta$. IL-1 receptor binding material from febrile patient urine was effectively purified with affinity column chromatography which conjugated with ON-1. This urinary material inhibited the thymocyte proliferation in a dosedependent manner. IL-l$\beta$ induced thymocyte proliferation activity was inhibited to 67.3% at 6 $\mu\textrm{g}$ of the purified urinary material. The result may suggest that this urinary material the purified urinary material. The result may suggest that this urinary material will have antagonic effect on IL-1 action mechanism and act IL-l$\beta$ inhibitor.

  • PDF

Expression of an Angiogenin Binding Peptide and Its Anti-Angiogenic Activity

  • Choi, Suk-Jung;Ahn, Mi-Won;Yoon, Kyoung-Bum;Park, Jong-Won
    • BMB Reports
    • /
    • v.31 no.5
    • /
    • pp.427-431
    • /
    • 1998
  • In the previous report (Choi et al., 1997), the angiogenin binding peptides identified from a phage-peptide library were analyzed by using the fusion proteins composed of the Escherichia coli maltose binding protein and its corresponding peptides. However, it was difficult to obtain a sufficient amount of the fusion proteins required for further analysis because of the low expression level. We now report a high level expression of the fusion protein and analysis of its anti-angiogenin activity. The use of strong T7 promoter and removal of signal sequence allowed about a 20-fold increase in the expression efficiency of the fusion protein. We were able to obtain about 10 mg of purified fusion protein from one liter of culture. The purified fusion protein showed angiogenin-specific affinity and inhibited the binding of biotinylated actin to human angiogenin at $IC_{50}$ of 0.6 mM. Its anti-angiogenin activity was also revealed by the chorioallantoic membrane assay.

  • PDF

Prediction of Relative Stability between TACE/Gelastatin and TACE/Gelastatin Hydroxamate

  • Nam, Ky-Youb;Han, Gyoon-Hee;Kim, Hwan-Mook;No, Kyoung-Tai
    • Bulletin of the Korean Chemical Society
    • /
    • v.31 no.11
    • /
    • pp.3291-3296
    • /
    • 2010
  • A gelastatins (1), natural MMP inhibitors, and their hydroxamate analogues (2) in TACE enzyme evaluated for discovery of potent TACE inhibitors. We have employed molecular dynamics simulations to compute the relative free energy of hydration and binding to TACE for gelastatin (1) and its hydroxamate analogue (2). The relative free energy difference is directly described in this article using the free energy perturbation approach as a means to accurately predict the TACE inhibitor of gelastatin analogues. The results show that the good agreement between the experimental and theoretical relative free energies of binding, gelastatin hydroxamate (2) binds stronger to TACE by -3.37 kcal/mol. The desolvation energy costs significantly reduced binding affinity, hydroxamate group associated with high desolvation energy formed strong favorable interactions with TACE with more than compensated for the solvation costs and therefore led to an improvement in relative binding affinity.

Characterization of the Binding Activity of Virginiae Butanolide C Binding Protein in Streptomyces virginiae (Streptomyces virginiae가 생산하는 Virginiae Butanolide C(VB-C) 결합단백질의 결합활성에 미치는 일반적 특성)

  • 김현수
    • Microbiology and Biotechnology Letters
    • /
    • v.20 no.3
    • /
    • pp.257-262
    • /
    • 1992
  • Virginiae butanolide (VB) is an autoregulator which triggers virginiamycin production in Strefltomyces virginiae. VB-C binding protein activity was investigated under various additives. The VB-C binding protein was almost fully observed in sotubte fraction (>90%) and the binding activity was optimum at pH 7.0. The VB-C binding activity was increased about 15% in 0.5 M KCI, whereas decreased about 60% in 20 mM $Mo^{6+}$. Chelating reagents (ethylenediarnine tetraacetic acid, ethyleneglycol bis(2-aminoethylether) tetraacetic acid, 8-hydroxyquinoline) and SH protecting reagents (rnercaptoethanol, dithiothreitol, thioglycerol) inhibited the VB-C binding activity about 30~55% and 3~20%, respectively. Serine protease inhibitor (phenyl methane sulfonyl fluoride), nucleotides (guanosine 5'-monophosphate, adenosine 3',5'-cyclic monophosphate), and phosphatases (alkaline, acid phosphatase) increased the VB-C binding activity about 17%, 6~20%, and 4- 13%, respectively.

  • PDF

Role of $NF-_{{\kappa}B}$ Binding Sites in the Regulation of Inducible Nitric Oxide Synthase by Tyrosine Kinase

  • Ryu, Young-Sue;Hong, Jang-Hee;Lim, Jong-Ho;Bae, So-Hyun;Ahn, Ihn-Sub;Seok, Jeong-Ho;Lee, Jae-Heun;Hur, Gang-Min
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.5 no.1
    • /
    • pp.55-63
    • /
    • 2001
  • In macrophages, lipopolysaccharide (LPS) alone or in combination with $interferon-{\gamma}\;(IFN-{\gamma})$ has been shown to release a nitric oxide (NO) through the increase of the transcription of the inducible nitric oxide synthase (iNOS) gene. To investigate the exact intracellular signaling pathway of the regulation of iNOS gene transcription by LPS plus $IFN-{\gamma},$ the effects of protein tyrosine kinase (PTK) inhibitor and protein kinase C (PKC) inhibitors on NO production, iNOS mRNA expression, nuclear $factor-_{\kappa}B\;(NF-_{\kappa}B)$ binding activity and the promoter activity of iNOS gene containing two $NF-_{\kappa}B$ sites have been examined in a mouse macrophage RAW 264.7 cells. LPS or $IFN-{\gamma}$ stimulated NO production, and their effect was enhanced synergistically by mixture of LPS and $IFN-{\gamma}.$ The PTK inhibitor such as tyrphostin reduced LPS plus $IFN-{\gamma}-induced$ NO production, iNOS mRNA expression and $NF-_{\kappa}B$ binding activity. In contrast, PKC inhibitors such as H-7, Ro-318220 and staurosporine did not show any effect on them. In addition, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that tyrphostin inhibited the iNOS promoter activity through the $NF-_{\kappa}B$ binding site, whereas PKC inhibitors did not. Taken together, these suggest that PTK, but not PKC pathway, is involved in the regulation of the iNOS gene transcription through the $NF-_{\kappa}B$ sites of iNOS promoter in RAW 264.7 macrophages by LPS plus $IFN-{\gamma}$.

  • PDF