17 research outputs found
Engineering yeast alcohol dehydrogenase. Replacing Trp54 by Leu broadens substrate specificity
Analysis of a crystal structure of alcohol dehydrogenase (Adh) from horse liver suggests that Trp54 in the homologous yeast alcohol dehydrogenase prevents the yeast enzyme from efficiently catalysing the oxidation of long-chain primary alcohols with branching at the 4 position (e.g. 4-methyl-1-pentanol, cinnamyl alcohol). This residue has been altered to Leu by site-directed mutagenesis. The alteration yields an enzyme that serves as an effective catalyst for both longer straight-chain primary alcohols and branched chain alcohol
Targeted DNA Methylation by a DNA Methyltransferase Coupled to a Triple Helix Forming Oligonucleotide To Down-Regulate the Epithelial Cell Adhesion Molecule
The epithelial cell adhesion molecule (EpCAM) is a membrane glycoprotein that has been identified as a marker of cancer-initiating cells. EpCAM is highly expressed on most carcinomas, and transient silencing of EpCAM expression leads to reduced oncogenic potential. To silence the EpCAM gene in a persistent manner via targeted DNA methylation, a low activity mutant (C141S) of the CpG-specific DNA methyltransferase M.SssI was coupled to a triple-helix-forming oligonucleotide (TFO−C141S) specifically designed for the EpCAM gene. Reporter plasmids encoding the green fluorescent protein under control of different EpCAM promoter fragments were treated with the TFO−C141S conjugate to determine the specificity of targeted DNA methylation in the context of a functional EpCAM promoter. Treatment of the plasmids with TFO−C141S resulted in efficient and specific methylation of the targeted CpG located directly downstream of the triple helix forming site (TFS). No background DNA methylation was observed neither in a 700 bp region of the EpCAM promoter nor in a 400 bp region of the reporter gene downstream of the TFS. Methylation of the target CpG did not have a detectable effect on promoter activity. This study shows that the combination of a specific TFO and a reduced activity methyltransferase variant can be used to target DNA methylation to predetermined sites with high specificity, allowing determination of crucial CpGs for promoter activity
Thiaheterohelicenes. 3. Donor Properties of a Series of Benzene-Capped Thiaheterohelicenes. Structure of a Tetrathianonahelicene and its TCNQ Salt.
Inner Sphere and Outer Sphere Electron Transfer to Methyl Iodide. Deuterium and 13C Kinetic Isotope Effects.
Thiaheterohelicenes. 1. Synthesis of Unsubstituted Thia[5]-, [9]- and [13]heterohelicenes.
pH and Ionic Strength Effects on Electron Transfer Rate Constants and Reduction Potentials of the Bacterial Di-Heme Protein Pseudomonas stutzeri Cytochrome c4.
Preparation of Heterobimetallic Cuboidal Clusters [M3NiS4(H2O)10]4+ (M = Mo, W) and Their Reactivity Towards CO.
Erforschung von biokompatiblen und korrosionsbestandigen Beschichtungen, die auf Titanlegierung Vt6 durch Elektroerosivemetallbearbeitung aufgetragen werden
В статье рассмотрены фазовый и химико-элементный составы покрытия для ортопедии и дентальной медицины, нанесенного на титановый сплав ВТ6методом электроискровой обработки металлов с целью предотвращения попадания с поверхности сплава в организм человека химических элементов, оказывающих токсическое воздействие