TY - JOUR A1 - Zeng, Ting A1 - Leimkühler, Silke A1 - Wollenberger, Ulla A1 - Fourmond, Vincent T1 - Transient Catalytic Voltammetry of Sulfite Oxidase Reveals Rate Limiting Conformational Changes JF - Journal of the American Chemical Society N2 - Sulfite oxidases are metalloenzymes that oxidize sulfite to sulfate at a molybdenum active site. In vertebrate sulfite oxidases, the electrons generated at the Mo center are transferred to an external electron acceptor via a heme domain, which can adopt two conformations: a “closed” conformation, suitable for internal electron transfer, and an “open” conformation suitable for intermolecular electron transfer. This conformational change is an integral part of the catalytic cycle. Sulfite oxidases have been wired to electrode surfaces, but their immobilization leads to a significant decrease in their catalytic activity, raising the question of the occurrence of the conformational change when the enzyme is on an electrode. We recorded and quantitatively modeled for the first time the transient response of the catalytic cycle of human sulfite oxidase immobilized on an electrode. We show that conformational changes still occur on the electrode, but at a lower rate than in solution, which is the reason for the decrease in activity of sulfite oxidases upon immobilization. Y1 - 2017 U6 - https://doi.org/10.1021/jacs.7b05480 SN - 0002-7863 VL - 139 SP - 11559 EP - 11567 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Luo, Ting A1 - Chen, Xiaoyi A1 - Zeng, Shufei A1 - Guan, Baozhang A1 - Hu, Bo A1 - Meng, Yu A1 - Liu, Fanna A1 - Wong, Taksui A1 - Lu, Yongpin A1 - Yun, Chen A1 - Hocher, Berthold A1 - Yin, Lianghong T1 - Bioinformatic identification of key genes and analysis of prognostic values in clear cell renal cell carcinoma JF - Oncology Letters N2 - The present study aimed to identify new key genes as potential biomarkers for the diagnosis, prognosis or targeted therapy of clear cell renal cell carcinoma (ccRCC). Three expression profiles (GSE36895, GSE46699 and GSE71963) were collected from Gene Expression Omnibus. GEO2R was used to identify differentially expressed genes (DEGs) in ccRCC tissues and normal samples. The Database for Annotation, Visualization and Integrated Discovery was utilized for functional and pathway enrichment analysis. STRING v10.5 and Molecular Complex Detection were used for protein-protein interaction (PPI) network construction and module analysis, respectively. Regulation network analyses were performed with the WebGestal tool. UALCAN web-portal was used for expression validation and survival analysis of hub genes in ccRCC patients from The Cancer Genome Atlas (TCGA). A total of 65 up- and 164 downregulated genes were identified as DEGs. DEGs were enriched with functional terms and pathways compactly related to ccRCC pathogenesis. Seventeen hub genes and one significant module were filtered out and selected from the PPI network. The differential expression of hub genes was verified in TCGA patients. Kaplan-Meier plot showed that high mRNA expression of enolase 2 (ENO2) was associated with short overall survival in ccRCC patients (P=0.023). High mRNA expression of cyclin D1 (CCND1) (P<0.001), fms related tyrosine kinase 1 (FLT1) (P=0.004), plasminogen (PLG) (P<0.001) and von Willebrand factor (VWF) (P=0.008) appeared to serve as favorable factors in survival. These findings indicate that the DEGs may be key genes in ccRCC pathogenesis and five genes, including ENO2, CCND1, PLT1, PLG and VWF, may serve as potential prognostic biomarkers in ccRCC. KW - clear cell renal cell carcinoma KW - bioinformatics KW - differentially expressed genes KW - biomarkers KW - Kaplan-Meier plot Y1 - 2018 U6 - https://doi.org/10.3892/ol.2018.8842 SN - 1792-1074 SN - 1792-1082 VL - 16 IS - 2 SP - 1747 EP - 1757 PB - Spandidos publ LTD CY - Athens ER - TY - JOUR A1 - Zeng, Ting A1 - Pankratov, Dmitry A1 - Falk, Magnus A1 - Leimkühler, Silke A1 - Shleev, Sergey A1 - Wollenberger, Ursula T1 - Miniature direct electron transfer based sulphite/oxygen enzymatic fuel cells JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics N2 - A direct electron transfer (DET) based sulphite/oxygen biofuel cell is reported that utilises human sulphite oxidase (hSOx) and Myrothecium verrucaria bilirubin oxidase (MvBOx) and nanostructured gold electrodes. For bioanode construction, the nanostructured gold microelectrodes were further modified with 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) to which polyethylene imine was covalently attached. hSOx was adsorbed onto this chemically modified nanostructured electrode with high surface loading of electroactive enzyme and in presence of sulphite high anodic bioelectrocatalytic currents were generated with an onset potential of 0.05 V vs. NHE. The biocathode contained MyBOx directly adsorbed to the deposited gold nanoparticles for cathodic oxygen reduction starting at 0.71 V vs. NHE. Both enzyme electrodes were integrated to a DET-type biofuel cell. Power densities of 8 and 1 mu W cm(-2) were achieved at 0.15 V and 0.45 V of cell voltages, respectively, with the membrane based biodevices under aerobic conditions. (C) 2014 Elsevier B.V. All rights reserved. KW - Enzymatic fuel cell KW - Microscale electrode KW - Direct electron transfer KW - Sulphite oxidase KW - Bilirubin oxidase Y1 - 2015 U6 - https://doi.org/10.1016/j.bios.2014.10.080 SN - 0956-5663 SN - 1873-4235 VL - 66 SP - 39 EP - 42 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zeng, Ting A1 - Leimkühler, Silke A1 - Koetz, Joachim A1 - Wollenberger, Ursula T1 - Effective Electrochemistry of Human Sulfite Oxidase Immobilized on Quantum-Dots-Modified Indium Tin Oxide Electrode JF - ACS applied materials & interfaces N2 - The bioelectrocatalytic sulfite oxidation by human sulfite oxidase (hSO) on indium tin oxide (ITO) is reported, which is facilitated by functionalizing of the electrode surface with polyethylenimine (PEI)-entrapped CdS nanoparticles and enzyme. hSO was assembled onto the electrode with a high surface loading of electroactive enzyme. In the presence of sulfite but without additional mediators, a high bioelectrocatalytic current was generated. Reference experiments with only PEI showed direct electron transfer and catalytic activity of hSO, but these were less pronounced. The application of the polyelectrolyte-entrapped quantum dots (QDs) on ITO electrodes provides a compatible surface for enzyme binding with promotion of electron transfer. Variations of the buffer solution conditions, e.g., ionic strength, pH, viscosity, and the effect of oxygen, were studied in order to understand intramolecular and heterogeneous electron transfer from hSO to the electrode. The results are consistent with a model derived for the enzyme by using flash photolysis in solution and spectroelectrochemistry and molecular dynamic simulations of hSO on monolayer-modified gold electrodes. Moreover, for the first time a photoelectrochemical electrode involving immobilized hSO is demonstrated where photoexcitation of the CdS/hSO-modified electrode lead to an enhanced generation of bioelectrocatalytic currents upon sulfite addition. Oxidation starts already at the redox potential of the electron transfer domain of hSO and is greatly increased by application of a small overpotential to the CdS/hSO-modified ITO. KW - human sulfite oxidase KW - direct electrochemistry KW - bioelectrocatalysis KW - photocurrent KW - CdS quantum dots Y1 - 2015 U6 - https://doi.org/10.1021/acsami.5b06665 SN - 1944-8244 VL - 7 IS - 38 SP - 21487 EP - 21494 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Zeng, Ting A1 - Frasca, Stefano A1 - Rumschöttel, Jens A1 - Koetz, Joachim A1 - Leimkühler, Silke A1 - Wollenberger, Ursula T1 - Role of Conductive Nanoparticles in the Direct Unmediated Bioelectrocatalysis of Immobilized Sulfite Oxidase JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis KW - Direct electron transfer KW - Protein voltammetry KW - Human sulfite oxidase KW - Bioelectrocatalysis KW - Nanoparticles Y1 - 2016 U6 - https://doi.org/10.1002/elan.201600246 SN - 1040-0397 SN - 1521-4109 VL - 28 SP - 2303 EP - 2310 PB - Wiley-VCH CY - Weinheim ER - TY - THES A1 - Zeng, Ting T1 - Nanoparticles promoted biocatalysis BT - Electrochemical investigation of human sulfite oxidase on nanoparticles modified electrodes Y1 - 2017 ER -