Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. ...Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. Characterization of the crude C12O showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C12O. It was suggested that strain QYY possessed an inducible and ferric-dependent C12O. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C12O was achieved by a HiTrap Q Sepharose column chromatography.展开更多
The selenomethionyl derivative of the thermo-stable catechol 2,3-dioxygenase (SeMet-TC23O) is expressed, purified and crystallized. By using multiwave length anoma-lous dispersion (MAD) phasing techniques, the crystal...The selenomethionyl derivative of the thermo-stable catechol 2,3-dioxygenase (SeMet-TC23O) is expressed, purified and crystallized. By using multiwave length anoma-lous dispersion (MAD) phasing techniques, the crystal structure of TC23O at 0.3 nm resolutions is determined. TC23O is a homotetramer. Each monomer is composed of N-terminal and C-terminal domains (residues 1-153 and 153-319, respectively). The two domains are proximately symmetric by a non-crystallographic axis. Each domain contains two characteristic motifs which are found in almost all of extradial dioxygenases.展开更多
In Northern Israel, olive mills discharge liquid waste causing contamination of subterranean aquifers with phenol, rendering them albeit temporarily, unfit for both drinking and irrigation. The impact of groundwater p...In Northern Israel, olive mills discharge liquid waste causing contamination of subterranean aquifers with phenol, rendering them albeit temporarily, unfit for both drinking and irrigation. The impact of groundwater pollution due to phenol spillage can be extensive. We developed a model system for the biodegradation of phenol-contaminated wastewater by the bacterium Corynebacterium glutamicum. Experiments consisting of suspended cultures demonstrated the native ability of this organism to utilize phenol for its metabolic pathways enabling degradation, at levels of nearly 100 ppm within 24 hours. With the use of bioinformatic data, a complete degradation pathway was constructed. Quantitative Real Time PCR analysis of the first two enzymes in this pathway revealed very distinct expression patterns and two different regulation mechanisms were postulated. Additionally, an electrospinning core-shell system was used to assemble electrospun microtubes containing bacteria on porous metallic carriers. We used these carriers as a new immobilization technique and demonstrated their significant phenol degrading capacity in a batch bioreactor configuration. This system demonstrates the feasibility of constructing a water treatment system for the management of phenol-contaminated water.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 50608011)the 39th Postdoctoral Funds of China (Grant No. 20060390983)
文摘Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. Characterization of the crude C12O showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C12O. It was suggested that strain QYY possessed an inducible and ferric-dependent C12O. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C12O was achieved by a HiTrap Q Sepharose column chromatography.
基金This workwas supported by the National Natural Science Foundation of China (Grant No. 30070161) the Hundreds Talents Program of the ChineseAcademy of Sciences.
文摘The selenomethionyl derivative of the thermo-stable catechol 2,3-dioxygenase (SeMet-TC23O) is expressed, purified and crystallized. By using multiwave length anoma-lous dispersion (MAD) phasing techniques, the crystal structure of TC23O at 0.3 nm resolutions is determined. TC23O is a homotetramer. Each monomer is composed of N-terminal and C-terminal domains (residues 1-153 and 153-319, respectively). The two domains are proximately symmetric by a non-crystallographic axis. Each domain contains two characteristic motifs which are found in almost all of extradial dioxygenases.
文摘In Northern Israel, olive mills discharge liquid waste causing contamination of subterranean aquifers with phenol, rendering them albeit temporarily, unfit for both drinking and irrigation. The impact of groundwater pollution due to phenol spillage can be extensive. We developed a model system for the biodegradation of phenol-contaminated wastewater by the bacterium Corynebacterium glutamicum. Experiments consisting of suspended cultures demonstrated the native ability of this organism to utilize phenol for its metabolic pathways enabling degradation, at levels of nearly 100 ppm within 24 hours. With the use of bioinformatic data, a complete degradation pathway was constructed. Quantitative Real Time PCR analysis of the first two enzymes in this pathway revealed very distinct expression patterns and two different regulation mechanisms were postulated. Additionally, an electrospinning core-shell system was used to assemble electrospun microtubes containing bacteria on porous metallic carriers. We used these carriers as a new immobilization technique and demonstrated their significant phenol degrading capacity in a batch bioreactor configuration. This system demonstrates the feasibility of constructing a water treatment system for the management of phenol-contaminated water.
