Thuy, T. T.; Anh, N. T. H.; Sung, T. V.; Dan, T. K.; Chinh, N. B.; Quang, N.; Franke, K.; Arnold, N.; Wessjohann, L.;Phytochemical study on the plants of the antidrug medication heantos 4: Part 4. Phthalides, fatty acids, oligosaccharide esters and miscellaneous compoundsVietnam J. Chem.51546-550(2013)
Thuy, T. T.; Anh, N. H.; Sung, T. V.; Dan, T. K.; Chinh, N. B.; Quang, N.; Franke, K.; Arnold, N.; Wessjohann, L.;Phytochemical study on the plants of the antidrug medication heantos 4: Part 1. Alkaloids and other nitrogen containing compoundsVietnam J. Chem.51185-189(2013)
Anh, N. T. H.; Thuy, T. T.; Sung, T. V.; Dan, T. K.; Chinh, N. B.; Quang, N.; Franke, K.; Arnold, N.; Wessjohann, L.;Phytochemical study on the plants of the antidrug medication heantos 4: Part 3. Homoisoflavonoid, flavonoid and phenolic compoundsVietnam J. Chem.51358-362(2013)
Anh, N. T. H.; Thuy, T. T.; Sung, T. V.; Dan, T. K.; Chinh, N. B.; Quang, N.; Franke, K.; Arnold, N.; Wessjohann, L.;Phytochemical study on the plants of the antidrug medication heantos 4: Part 2. Terpenoid- and steroid compoundsVietnam J. Chem.51190-194(2013)
Khamko, V. A.; Dien, P. H.; Schmidt, J.; Quang, D. N.;Cytotoxic and antimicrobial constituents from the roots of Stemona cochinchinesis in LaosVietnam J. Chem.50203-206(2012)
Barak, N. N.; Neumann, P.; Sevvana, M.; Schutkowski, M.; Naumann, K.; Malešević, M.; Reichardt, H.; Fischer, G.; Stubbs, M. T.; Ferrari, D. M.;Crystal Structure and Functional Analysis of the Protein Disulfide Isomerase-Related Protein ERp29J. Mol. Biol.3851630-1642(2009)DOI: 10.1016/j.jmb.2008.11.052
The protein disulfide isomerase-related protein ERp29 is a putative chaperone involved in processing and secretion of secretory proteins. Until now, however, both the structure and the exact nature of interacting substrates remained unclear. We provide for the first time a crystal structure of human ERp29, refined to 2.9 Å, and show that the protein has considerable structural homology to its Drosophila homolog Wind. We show that ERp29 binds directly not only to thyroglobulin and thyroglobulin-derived peptides in vitro but also to the Wind client protein Pipe and Pipe-derived peptides, although it fails to process Pipe in vivo. A monomeric mutant of ERp29 and a D domain mutant in which the second peptide binding site is inactivated also bind protein substrates, indicating that the monomeric thioredoxin domain is sufficient for client protein binding. Indeed, the b domains of ERp29 or Wind, expressed alone, are sufficient for binding proteins and peptides. Interacting peptides have in common two or more aromatic residues, with stronger binding for sequences with overall basic character. Thus, the data allow a view of the two putative peptide binding sites of ERp29 and indicate that the apparent, different processing activity of the human and Drosophila proteins in vivo does not stem from differences in peptide binding properties.
Publikation
Kopycki, J. G.; Rauh, D.; Chumanevich, A. A.; Neumann, P.; Vogt, T.; Stubbs, M. T.;Biochemical and Structural Analysis of Substrate Promiscuity in Plant Mg2+-Dependent O-MethyltransferasesJ. Mol. Biol.378154-164(2008)DOI: 10.1016/j.jmb.2008.02.019
Plant S-adenosyl-l-methionine-dependent class I natural product O-methyltransferases (OMTs), related to animal catechol OMTs, are dependent on bivalent cations and strictly specific for the meta position of aromatic vicinal dihydroxy groups. While the primary activity of these class I enzymes is methylation of caffeoyl coenzyme A OMTs, a distinct subset is able to methylate a wider range of substrates, characterized by the promiscuous phenylpropanoid and flavonoid OMT. The observed broad substrate specificity resides in two regions: the N-terminus and a variable insertion loop near the C-terminus, which displays the lowest degree of sequence conservation between the two subfamilies. Structural and biochemical data, based on site-directed mutagenesis and domain exchange between the two enzyme types, present evidence that only small topological changes among otherwise highly conserved 3-D structures are sufficient to differentiate between an enzymatic generalist and an enzymatic specialist in plant natural product methylation.
Publikation
Thuy, T. T.; Sung, T. V.; Franke, K.; Arnold, N.; Wessjohann, L.;Flavonone-C-glycosides from the seeds of Zizyphus Jujuba Mill var. Spinosa HuVietnam J. Chem.1-8(2007)
Ninh, P. T.; Anh, N. T. H.; Sung, T. V.; Wessjohann, L.;Studies on chemical constituents of the roots of Polygala sp.: II - Further phenylpropanoide sucrose estersVietnam J. Chem.45518-522(2007)
Anh, N. T. H.; Sung, T. V.; Arnold, N.; Wessjohann, L.;Chemical constituents of Zizyphus sativa Gaertn fruits. Part III - AlkaloidsVietnam J. Chem.45237-240(2007)
Two alkaloids have been isolated from Z. sativa fruits besides butane-2,3-diol and glycerol. The structures of alkaloids were established as stepharine and 1,2-dimethoxy,5,6,6a,7-tetrahydro-4H-dibenzo-quinoline by using MS, NMR spectroscopic data and by comparison with reported data.