19 research outputs found

    Crystallization and X-ray crystallographic analysis of recombinant TylP, a putative γ-butyrolactone receptor protein from Streptomyces fradiae

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    TylP is one of five regulatory proteins involved in the regulation of antibiotic (tylosin) production, morphological and physiological differentiation in Streptomyces fradiae. Its function is similar to those of various γ-butyrolactone receptor proteins. In this report, N-terminally His-tagged recombinant TylP protein (rTylP) was overproduced in Escherichia coli and purified to homogeneity. The rTylP protein was crystallized from a reservoir solution comprising 34%(v/v) ethylene glycol and 5%(v/v) glycerol. The protein crystals diffracted X-rays to 3.05 Å resolution and belonged to the trigonal space group P3121, with unit-cell parameters a = b = 126.62, c = 95.63 Å

    Cloning, expression, purification, crystallization and X-ray crystallographic analysis of recombinant human C1ORF123 protein

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    C1ORF123 is a human hypothetical protein found in open reading frame 123 of chromosome 1. The protein belongs to the DUF866 protein family comprising eukaryote-conserved proteins with unknown function. Recent proteomic and bioinformatic analyses identified the presence of C1ORF123 in brain, frontal cortex and synapses, as well as its involvement in endocrine function and polycystic ovary syndrome (PCOS), indicating the importance of its biological role. In order to provide a better understanding of the biological function of the human C1ORF123 protein, the characterization and analysis of recombinant C1ORF123 (rC1ORF123), including overexpression and purification, verification by mass spectrometry and a Western blot using anti-C1ORF123 antibodies, crystallization and X-ray diffraction analysis of the protein crystals, are reported here. The rC1ORF123 protein was crystallized by the hanging-drop vapor-diffusion method with a reservoir solution comprised of 20% PEG 3350, 0.2 M magnesium chloride hexahydrate, 0.1 M sodium citrate pH 6.5. The crystals diffracted to 1.9 Å resolution and belonged to an orthorhombic space group with unit-cell parameters a = 59.32, b = 65.35, c = 95.05 Å. The calculated Matthews coefficient (VM) value of 2.27 Å3 Da−1 suggests that there are two molecules per asymmetric unit, with an estimated solvent content of 45.7%

    Genes for degradation and utilization of uronic acid-containing polysaccharides of a marine bacterium Catenovulum sp. CCB-QB4

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    Background Oligosaccharides from polysaccharides containing uronic acids are known to have many useful bioactivities. Thus, polysaccharide lyases (PLs) and glycoside hydrolases (GHs) involved in producing the oligosaccharides have attracted interest in both medical and industrial settings. The numerous polysaccharide lyases and glycoside hydrolases involved in producing the oligosaccharides were isolated from soil and marine microorganisms. Our previous report demonstrated that an agar-degrading bacterium, Catenovulum sp. CCB-QB4, isolated from a coastal area of Penang, Malaysia, possessed 183 glycoside hydrolases and 43 polysaccharide lyases in the genome. We expected that the strain might degrade and use uronic acid-containing polysaccharides as a carbon source, indicating that the strain has a potential for a source of novel genes for degrading the polysaccharides. Methods To confirm the expectation, the QB4 cells were cultured in artificial seawater media with uronic acid-containing polysaccharides, namely alginate, pectin (and saturated galacturonate), ulvan, and gellan gum, and the growth was observed. The genes involved in degradation and utilization of uronic acid-containing polysaccharides were explored in the QB4 genome using CAZy analysis and BlastP analysis. Results The QB4 cells were capable of using these polysaccharides as a carbon source, and especially, the cells exhibited a robust growth in the presence of alginate. 28 PLs and 22 GHs related to the degradation of these polysaccharides were found in the QB4 genome based on the CAZy database. Eleven polysaccharide lyases and 16 glycoside hydrolases contained lipobox motif, indicating that these enzymes play an important role in degrading the polysaccharides. Fourteen of 28 polysaccharide lyases were classified into ulvan lyase, and the QB4 genome possessed the most abundant ulvan lyase genes in the CAZy database. Besides, genes involved in uronic acid metabolisms were also present in the genome. These results were consistent with the cell growth. In the pectin metabolic pathway, the strain had genes for three different pathways. However, the growth experiment using saturated galacturonate exhibited that the strain can only use the pathway related to unsaturated galacturonate

    Subprime mortgage default rates, spread volatility and contagion to stock markets.

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    This thesis studies (i) the impact of the subprime mortgage crisis on the mortgage-backed CDS market and equity markets using the ABX.HE indices and the S&P 500 and DJIA Index, (ii) the underlying parameters such as implied spreads, default probabilities and long-term implications of the subprime mortgage crisis

    Identification of peptide binding sequence of TRIM25 on 14-3-3σ by bioinformatics and biophysical techniques

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    14-3-3σ protein is one of the seven isoforms from the highly conserved eukaryotic 14-3-3 protein family. Downregulation of 14-3-3σ expression has been observed in various tumors. TRIM25 is responsible for the proteolytic degradation of 14-3-3σ, in which abrogation of TRIM25 suppressed tumor growth through 14-3-3σ upregulation. However, to date, the exact 14-3-3σ interacting residues of TRIM25 have yet to be resolved. Thus, this study attempts to identify the peptide binding sequence of TRIM25 on 14-3-3σ via both bioinformatics and biophysical techniques. Multiple sequence alignment of the CC domain of TRIM25 revealed five potential peptide binding sequences (Peptide 1–5). Nuclear magnetic resonance (NMR) assay (1H CPMG) identified Peptide 1 as an important sequence for binding to 14-3-3σ. Competition NMR assay suggested that Peptide 1 binds to the amphipathic pocket of 14-3-3σ with an estimated KD of 116.4 µM by isothermal titration calorimetry. Further in silico docking and molecular dynamics simulations studies proposed that Peptide 1 is likely to interact with Lys49, Arg56, Arg129, and Tyr130 residues at the amphipathic pocket of 14-3-3σ. These results suggest that Peptide 1 may serve as a biological probe or a template to design inhibitors of TRIM25-14-3-3σ interaction as a potentially novel class of anticancer agents. Communicated by Ramaswamy H. Sarma</p

    Crystal structure of Anoxybacillus α-amylase provides insights into maltose binding of a new glycosyl hydrolase subclass

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    A new subfamily of glycosyl hydrolase family GH13 was recently proposed for α-amylases from Anoxybacillus species (ASKA and ADTA), Geobacillus thermoleovorans (GTA, Pizzo, and GtamyII), Bacillus aquimaris (BaqA), and 95 other putative protein homologues. To understand this new GH13 subfamily, we report crystal structures of truncated ASKA (TASKA). ASKA is a thermostable enzyme capable of producing high levels of maltose. Unlike GTA, biochemical analysis showed that Ca2+ ion supplementation enhances the catalytic activities of ASKA and TASKA. The crystal structures reveal the presence of four Ca2+ ion binding sites, with three of these binding sites are highly conserved among Anoxybacillus α-amylases. This work provides structural insights into this new GH13 subfamily both in the apo form and in complex with maltose. Furthermore, structural comparison of TASKA and GTA provides an overview of the conformational changes accompanying maltose binding at each subsite
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