Crystallization and preliminary crystallographic analysis of a 2,3-dihydroxybiphenyl dioxygenase fromPseudomonas sp. strain KKS102 having polychlorinated biphenyl (PCB)-degrading activity

1995 ◽  
Vol 22 (3) ◽  
pp. 284-286 ◽  
Author(s):  
Kazuyuki Sugiyama ◽  
Hiroki Narita ◽  
Takeshi Yamamoto ◽  
Toshiya Senda ◽  
Kazuhide Kimbara ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Crystallographic Analysis ◽  
Dihydroxybiphenyl Dioxygenase

scholarly journals Evolutionarily Divergent Extradiol Dioxygenases Possess Higher Specificities for Polychlorinated Biphenyl Metabolites

2005 ◽  
Vol 187 (2) ◽  
pp. 415-421 ◽  
Author(s):  
Pascal D. Fortin ◽  
Andy T.-F. Lo ◽  
María-Amparo Haro ◽  
Stefan R. Kaschabek ◽  
Walter Reineke ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Substrate Binding ◽  
Structural Data ◽  
Binding Pocket ◽  
Distal Portion ◽  
The Other ◽  
Substrate Binding Pocket ◽  
Dihydroxybiphenyl Dioxygenase ◽  
Extradiol Dioxygenases ◽  
Better Than

ABSTRACT The reactivities of four evolutionarily divergent extradiol dioxygenases towards mono-, di-, and trichlorinated (triCl) 2,3-dihydroxybiphenyls (DHBs) were investigated: 2,3-dihydroxybiphenyl dioxygenase (EC 1.13.11.39) from Burkholderia sp. strain LB400 (DHBDLB400), DHBDP6-I and DHBDP6-III from Rhodococcus globerulus P6, and 2,2′,3-trihydroxybiphenyl dioxygenase from Sphingomonas sp. strain RW1 (THBDRW1). The specificity of each isozyme for particular DHBs differed by up to 3 orders of magnitude. Interestingly, the K m app values of each isozyme for the tested polychlorinated DHBs were invariably lower than those of monochlorinated DHBs. Moreover, each enzyme cleaved at least one of the tested chlorinated (Cl) DHBs better than it cleaved DHB (e.g., apparent specificity constants for 3′,5′-dichlorinated [diCl] DHB were 2 to 13.4 times higher than for DHB). These results are consistent with structural data and modeling studies which indicate that the substrate-binding pocket of the DHBDs is hydrophobic and can accommodate the Cl DHBs, particularly in the distal portion of the pocket. Although the activity of DHBDP6-III was generally lower than that of the other three enzymes, six of eight tested Cl DHBs were better substrates for DHBDP6-III than was DHB. Indeed, DHBDP6-III had the highest apparent specificity for 4,3′,5′-triCl DHB and cleaved this compound better than two of the other enzymes. Of the four enzymes, THBDRW1 had the highest specificity for 2′-Cl DHB and was at least five times more resistant to inactivation by 2′-Cl DHB, consistent with the similarity between the latter and 2,2′,3-trihydroxybiphenyl. Nonetheless, THBDRW1 had the lowest specificity for 2′,6′-diCl DHB and, like the other enzymes, was unable to cleave this critical PCB metabolite (k cat app < 0.001 s−1).

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Fine Structural Alterations in Thyroid Follicular Cells (FC) and Changes in Serum Thyroxine Produced by Feeding Polychlorinated Biphenyl (PCB) to Rats

1977 ◽  
Vol 35 ◽  
pp. 498-499
Author(s):  
W.T. Collins ◽  
Charles C. Capen ◽  
Louis Kasza
Keyword(s):  
Feed Efficiency ◽  
Polychlorinated Biphenyl ◽  
Serum Proteins ◽  
Skin Lesions ◽  
Hepatic Necrosis ◽  
Ultrastructural Changes ◽  
Lymphoid Tissues ◽  
Heat Transfer Fluids ◽  
Thyroid Follicular Cells ◽  
Peripheral Metabolism

The widespread contamination of the environment with PCB, a compound used extensively by industry in hydraulic and heat transfer fluids as well as plasticizers and solvents in adhesives and sealants, has resulted in detectable tissue levels in a large portion of the human population, domestic animals, and wildlife. Intoxication with PCB produces severe hepatic necrosis, degeneration of lymphoid tissues and kidney, skin lesions, decreased reproductive performance, reduced feed efficiency, and decreased weight gain. PCB also has been reported to reduce the binding of thyroid hormone to serum proteins and enhance the peripheral metabolism of thyroxine with increased excretion of thyroxine-glucuronide in the bile (Bastomsky, Endocrinology 95: 1150-1155, 1974).The objectives of this investigation were (1) to investigate the histopathologic, histochemical, and ultrastructural changes in thyroid FC produced by the acute (4 week) and chronic (12 week) administration of low (50 ppm) and high (500 ppm) doses of PCB to rats, (2) to correlate these alterations to changes in serum immunoreactive thyroxine concentration, and (3) to investigate the persistence of the effects of PCB on the thyroid gland.

Some Observations on Intra-Mitochondrial Crystals

1977 ◽  
Vol 35 ◽  
pp. 406-407
Author(s):  
J. A. Clarke ◽  
D. N. Landon ◽  
P. R. Ward
Keyword(s):  
Cytochrome B ◽  
Mitochondrial Myopathy ◽  
Crystallographic Analysis ◽  
Mitochondrial Membranes ◽  
Electron Microscopes ◽  
Muscle Biopsies

Intra-mitochondrial crystals have been noted in muscle biopsies from patients in a wide variety of diseased states. As far as we are aware, none of these crystals have been subjected to detailed crystallographic analysis. Recently, similar crystals were observed in a biopsy from a patient with a mitochondrial myopathy, characterised by a deficiency in reducible cytochrome b (Morgan-Hughes, J. A., Darveniza, P., Kahn, S. N., Landon, D. N., Sherratt, R. M., Land, J. M. and Clark, J. B., 1977, Brain, In Press). Aldehyde-fixed, osmicated resin imbedded material was examined using Siemens, JEOL and Phillips electron microscopes with goniometer specimen stages. The crystals generally lay between the outer and inner mitochondrial membranes and measured 1 - 3 μm in length and 0.1 - 0.3 μm in width. Characteristically, these crystals revealed specific periodicities.

Polychlorinated biphenyl induced hepatocyte alterations

1987 ◽  
Vol 45 ◽  
pp. 716-717
Author(s):  
D.N. Collins ◽  
J.N. Turner ◽  
K.O. Brosch ◽  
R.F. Seegal
Keyword(s):  
Lipid Droplets ◽  
Wistar Rats ◽  
Homovanillic Acid ◽  
Polychlorinated Biphenyl ◽  
Corn Oil ◽  
Environmental Pollutants ◽  
Short Term ◽  
Pcb Congeners ◽  
Urinary Levels ◽  
The Brain

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).

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