YciF is a protein that is up-regulated when bacteria experience stress conditions, and is highly conserved in a range of bacterial species. YciF has no known structure or biochemical function. To learn more about its potential molecular function and its role in the bacterial stress response, we solved the crystal structure of YciF at 2.0 Å resolution by the multiple wavelength anomalous diffraction (MAD) technique. YciF is a dimer in solution, and forms a homodimer in the crystal asymmetric unit. The two monomers form a dimer with a molecular twofold axis, with a significant burial of solvent-accessible surface area. The protein is an all-alpha protein composed of five helices: a four-helix bundle, and a short additional helix at the dimer interface. The protein is structurally similar to portions of the diiron-containing proteins, rubrerythrin and the Bacillus anthracis Dlp-2.

No abstract

The mRNA of Escherichia coli yedU gene is induced 31-fold upon heat shock. The 31-kD YedU protein, also calls Hsp31, is highly conserved in several human pathogens and has chaperone activity. We solved the crystal structure of YedU at 2.2 Å resolution. YedU monomer has an ␣/␤/␣ sandwich domain and a small ␣/␤ domain. YedU is a dimer in solution, and its crystal structure indicates that a significant amount of surface area is buried upon dimerization. There is an extended hydrophobic patch that crosses the dimer interface on the surface of the protein. This hydrophobic patch is likely the substrate-binding site responsible for the chaperone activity. The structure also reveals a potential protease-like catalytic triad composed of Cys184, His185, and Asp213, although no enzymatic activity could be identified. YedU coordinates a metal ion using His85, His122, and Glu90. This 2-His-1-carboxylate motif is present in carboxypeptidase A (a zinc enzyme), and a number of dioxygenases and hydroxylases that utilize iron as a cofactor, suggesting another potential function for YedU.Keywords: YedU; Hsp31; X-ray crystallography; chaperone; catalytic triad; metal binding protein Many bacterial genes encoding chaperones, proteases, transcription regulators, and other proteins are activated upon heat shock. Chaperones and proteases can increase a bacterium's ability to survive under stress conditions by helping proteins fold and by removing damaged polypeptides. The mRNA of the Escherichia coli yedU gene is induced 31-fold upon heat shock (Richmond et al. 1999). Expression of the YedU protein, the 282-residue product of the yedU gene, is enhanced in an hns-deletion strain (Yoshida et al. 1993), a genetic background known to derepress stress gene expression (Hengge-Aronis 1996). Primary sequence analysis shows that YedU is highly conserved in several microbial genomes (Fig. 1).It was recently reported that YedU has chaperone activity (Sastry et al. 2002;Malki et al. 2003). At 45°C, it can suppress the aggregation of folding intermediates of alcohol dehydrogenase (ADH) and promote its reactivation when the temperature is dropped to 23°C. Furthermore, 1-anilino-8-naphthalenesulfonate (bis-ANS) binding experiments suggest that hydrophobic domains of YedU are more exposed at the elevated temperature. Although an ATPase activity of YedU has not been detected, ATP can suppress its chaperone activity at 45°C in vitro.Remote homology (less than 15% identity) is detected between YedU and the PfpI intracellular cysteine protease family using PSI-BLAST (Altschul et al. 1997). YedU is almost twice as long as the members of the PfpI protease 2303family, due to an N-terminal extension and several large insertions. PH1704 from Pyrococcus horikoshii is the first member of the PfpI protease family whose structure has been determined (Du et al. 2000; PDB accession code 1G2I). The active form of PH1704 is a hexamer, and its catalytic triad is composed of Cys100, His101, and a Glu474 contributed by an adjacent subunit. Cys100 and His101 are...

Preparation of oxygen-rich porous carbon from low rank coal.

Decoupled the activation process into gas–solid diffusion and reaction, and revealed an evolution mechanism of pore structure during the preparation of activated carbon.

A novel truncated form (residues 1–214, with a randomized C-terminal tail) of the ligand-binding extracellular domain (ECD) of the human α1 glycine receptor (GlyR), with amino acids from the corresponding sequence of an acetylcholine binding protein (AChBP) substituted for two relatively hydrophobic membrane-proximal loops, was overexpressed using a baculovirus expression system. The mutant GlyR ECD, named GlyBP, was present in both soluble and membrane-associated fractions after cell lysis, though only the latter appeared to be in a native-like conformation capable of binding strychnine, a GlyR specific antagonist. The membrane-associated GlyBP was solubilized and detergent/lipid/protein micelles were affinity purified. After detergent removal, GlyBP may be isolated in either aqueous or vesicular form. Binding assays and spectroscopic studies using circular dichroism and FRET are consistent with both forms adopting equivalent native-like conformations. Thus GlyBP may be isolated as a soluble or membrane-associated assembly that serves as a structural and functional homolog of the ECD of GlyR.

The putative receptor-binding domain (domain III) of the flavivirus Langat envelope glycoprotein has been crystallized using the hanging-drop vapor-diffusion method at 277 K. Two distinct crystal morphologies were observed to grow under the same conditions. The crystal forms both belong to a trigonal space group, P3(1)21 or P3(2)21, with unit-cell parameters a = 80.93, c = 132.1 A and a = 104.8, c = 219.5 A for forms I and II, respectively. Complete data sets to 2.9 and 3.35 A, respectively, have been collected at 100 K with Cu Kalpha X-rays from a rotating-anode generator.

Background Accumulating evidence has proved the significant influence of long non-coding RNAs (lncRNAs) in cancer formation and development, including PCa. Methods The role of LINC00689 in PCa was confirmed by RT-qPCR, MTT, colony formation, flow cytometry, western blot and transwell assays. Besides, the binding ability between LINC00689 and miR-496 was validated by using luciferase reporter assay. Then RT-qPCR, RIP and luciferase reporter and western blot assays were employed to verify the interactions among LINC00689, miR-496 and CTNNB1. Furthermore, the rescuing role of CTNNB1 in Wnt pathway was proved by RT-qPCR, TOP/FOP Flash and western blot assays. Results LINC00689 was upregulated in PCa tissues and cells as well as at the terminal stage. Further, knock down of LINC00689 repressed PCa cell proliferation, migration and invasion, and initiated PCa cell apoptosis. Additionally, miR-496 inhibitor and pcDNA3.1/CTNNB1 could neutralize the prohibitive effects of LINC00689 silencing on cell proliferation, migration and invasion, meanwhile, could offset the encouraging role of knocking down LINC00689 in cell apoptosis. Moreover, CTNNB1 upregulation exerted redemptive function in Wnt pathway inhibited by LINC00689 depletion. Conclusions To sum up, LINC00689 promotes PCa progression via regulating miR-496/CTNNB1 to activate Wnt pathway, which may contribute to research about new targets for PCa treatment.