Abstract:
:Several strains of Sphingobium chlorophenolicum have been isolated from soil that was heavily contaminated with pentachlorophenol (PCP), a toxic pesticide introduced in the 1930s. S. chlorophenolicum appears to have assembled a poorly functioning pathway for degradation of PCP by patching enzymes recruited via two independent horizontal gene transfer events into an existing metabolic pathway. Flux through the pathway is limited by PCP hydroxylase. PCP hydroxylase is a dimeric protein that belongs to the family of flavin-dependent phenol hydroxylases. In the presence of NADPH, PCP hydroxylase converts PCP to tetrachlorobenzoquinone (TCBQ). The k(cat) for PCP (0.024 s(-1)) is very low, suggesting that the enzyme is not well evolved for turnover of this substrate. Structure-activity studies reveal that substrate binding and activity are enhanced by a low pK(a) for the phenolic proton, increased hydrophobicity, and the presence of a substituent ortho to the hydroxyl group of the phenol. PCP hydroxylase exhibits substantial uncoupling; the C4a-hydroxyflavin intermediate, instead of hydroxylating the substrate, can decompose to produce H(2)O(2) in a futile cycle that consumes NADPH. The extent of uncoupling varies from 0 to 100% with different substrates. The extent of uncoupling is increased by the presence of bulky substituents at position 3, 4, or 5 and decreased by the presence of a chlorine in the ortho position. The effectiveness of PCP hydroxylase is additionally hindered by its promiscuous activity with tetrachlorohydroquinone (TCHQ), a downstream metabolite in the degradation pathway. The conversion of TCHQ to TCBQ reverses flux through the pathway. Substantial uncoupling also occurs during the reaction with TCHQ.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Hlouchova K,Rudolph J,Pietari JM,Behlen LS,Copley SDdoi
10.1021/bi300261psubject
Has Abstractpub_date
2012-05-08 00:00:00pages
3848-60issue
18eissn
0006-2960issn
1520-4995journal_volume
51pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Starting from a standard unfolded state (3.0 M guanidine hydrochloride, pH 7.2), the kinetics of refolding of iso-2-cytochrome c have been investigated as a function of final pH between pH 3 and pH 10. Absorbance in the ultraviolet and visible spectral regions and tryptophan fluorescence are used to monitor folding. O...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00419a020
更新日期:1988-09-20 00:00:00
abstract::The light oxygen voltage-sensing (LOV) domain plays a crucial role in blue light (BL) sensing in plants and microorganisms. LOV domains are usually associated with the effector domains and regulate the activities of effector domains in a BL-dependent manner. Photozipper (PZ) is monomeric in the dark state. BL induces ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b01045
更新日期:2018-02-06 00:00:00
abstract::The stability and folding kinetics of wild-type and a mutant staphylococcal nuclease (SNase) at neutral pH are significantly perturbed by the presence of moderate to high concentrations of salts. Very substantial increases in stability toward thermal and urea denaturation were observed; for example, 0.4 M sodium sulfa...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000861k
更新日期:2001-02-20 00:00:00
abstract::We have studied the hydrogen-exchange kinetics of hemoglobin A0 as a function of ligand, CO, saturation. In the noncooperative system, azide binding to methemoglobin, the alterations in exchange kinetics are proportional to the average degree of ligation. However, in the case of CO binding to deoxyhemoglobin the chang...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00297a015
更新日期:1984-01-17 00:00:00
abstract::To determine the energetic and structural consequences of placing a charged group within the core of a protein, two "buried charge" mutants, Met 102----Lys (M102K) and Leu 133----Asp (L133D) were constructed in phage T4 lysozyme. Both proteins fold at neutral pH, although they are substantially less stable than wild t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00113a006
更新日期:1991-12-10 00:00:00
abstract::Ammonia binds directly to the oxygen-evolving complex of photosystem II (PSII) upon formation of the S2 intermediate, as evidenced by electron paramagnetic resonance spectroscopy. We explore the binding mode by using quantum mechanics/molecular mechanics methods and simulations of extended X-ray absorption fine struct...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00974
更新日期:2015-09-29 00:00:00
abstract::The interaction between the calcium binding and inhibitory components of troponin is central to the regulation of muscle contraction. In this work, two-dimensional heteronuclear single-quantum coherence nuclear magnetic resonance (2D-¿1H,15N¿-HSQC NMR) spectroscopy was used to determine the stoichiometry, affinity, an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi992579n
更新日期:2000-03-21 00:00:00
abstract::α-Synuclein (α-Syn) oligomerization and amyloid formation are associated with Parkinson's disease (PD) pathogenesis. Studying familial α-Syn mutants associated with early onset PD has therapeutic importance. Here we report the aggregation kinetics and other biophysical properties of a newly discovered PD associated Fi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi5010365
更新日期:2014-10-21 00:00:00
abstract::The role of interleukin-8 (IL-8) and related CXC chemokines has been demonstrated in many human diseases. However, more profound studies, e.g., by blocking the effect of these inflammatory mediators, request animal models and hence the identification of all human counterparts for commonly used laboratory animals. In t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0011227
更新日期:2000-11-28 00:00:00
abstract::The human, cytosolic enzyme isocitrate dehydrogenase 1 (IDH1) reversibly converts isocitrate to α-ketoglutarate (αKG). Cancer-associated somatic mutations in IDH1 result in a loss of this normal function but a gain in a new or neomorphic ability to convert αKG to the oncometabolite 2-hydroxyglutarate (2HG). To improve...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi400514k
更新日期:2013-07-02 00:00:00
abstract::Defects in the MMACHC gene represent the most common disorder of cobalamin (Cbl) metabolism, affecting synthesis of the enzyme cofactors adenosyl-Cbl and methyl-Cbl. The encoded MMACHC protein binds intracellular Cbl derivatives with different upper axial ligands and exhibits flavin mononucleotide (FMN)-dependent decy...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300150y
更新日期:2012-06-26 00:00:00
abstract::In order to gain insight into the structure of human parathyroid hormone (hPTH), four fragments [hPTH(1-34), hPTH(18-48), hPTH(28-48), and hPTH(53-84)], which cover all regions of the intact hormone, have been investigated by CD and NMR spectroscopy in combination with distance geometry, and restrained molecular dynam...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00173a010
更新日期:1994-02-22 00:00:00
abstract::The gene coding for the enzyme 2,3-dihydroxybenzoate-AMP ligase (2,3DHB-AMP ligase), responsible for activating 2,3-dihydroxybenzoic acid in the biosynthesis of the siderophore enterobactin, has been subcloned into the multicopy plasmid pKK223-3 and overproduced in a strain of Escherichia coli. The protein is an alpha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00443a008
更新日期:1989-08-22 00:00:00
abstract::Actin depolymerizing activity in serum can be attributed to the two proteins brevin and vitamin D binding protein (DBP). To investigate their mechanisms of action, we used a number of techniques, including procedures involving the fluorescent pyrene-labeled actin probe, to compare the interaction of the two proteins w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00308a030
更新日期:1984-06-19 00:00:00
abstract::Retinitis pigmentosa (RP), a neurodegenerative disorder, can arise from single point mutations in rhodopsin, leading to a cascade of protein instability, misfolding, aggregation, rod cell death, retinal degeneration, and ultimately blindness. Divalent cations, such as zinc and copper, have allosteric effects on misfol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi800968w
更新日期:2009-03-03 00:00:00
abstract::Several peptides contained within the C-terminal sequence of the B2 subunit of Escherichia coli ribonucleotide reductase (RNR) were investigated for their ability to inhibit the enzyme, presumably by interfering with association of the B1 and B2 subunits. AcYLVGQIDSE, corresponding by sequence homology to a nonapeptid...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00247a008
更新日期:1991-08-20 00:00:00
abstract::We examine the effect of cargo-motor linkage stiffness on the mechanobiological properties of the molecular motor myosin VI. We use the programmability of DNA nanostructures to modulate cargo-motor linkage stiffness and combine it with high-precision optical trapping measurements to measure the effect of linkage stiff...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.9b00422
更新日期:2019-11-26 00:00:00
abstract::The crystal structure of the complex between the quinoprotein methylamine dehydrogenase (MADH) and the type I blue copper protein amicyanin, both from Paracoccus denitrificans, has been determined at 2.5-A resolution using molecular replacement. The search model was MADH from Thiobacillus versutus. The amicyanin could...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00136a006
更新日期:1992-06-02 00:00:00
abstract::Binding studies of the interaction of immobilized 1alpha- and 17alpha-aminoalkyl derivatives of 5alpha-dihydrotestosterone (DHT) with purified N-deglycosylated homodimeric human sex hormone-binding globulin (SHBG) were performed using a surface plasmon resonance biosensor. These 1alpha- and 17alpha-derivatives with sp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035269k
更新日期:2003-11-25 00:00:00
abstract::Soluble guanylate cyclase (sGC) is a heterodimeric hemoprotein composed of alpha1 and beta1 subunits. sGC is activated by nitric oxide (NO) and therefore plays a central role in NO signal transduction. Activation of sGC by NO is believed to be mediated by the interaction between NO and the heme of sGC. Spectroscopic a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971825x
更新日期:1997-12-16 00:00:00
abstract::Membrane preparations from two independent ouabain-resistant HeLa cell clones, HI-B1 and HI-C1, each appear to contain two species of (Na,K)ATPase. Two-thirds of the total (Na,K)ATPase in each mutant is indistinguishable from the enzyme in preparations of wild type cells with respect to ouabain binding, ouabain inhibi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00642a600
更新日期:1977-11-15 00:00:00
abstract::Illuminating Ca2+-depleted photosystem (PS) II membranes generated two new EPR signals at g = 11 and 15 by perpendicular and parallel polarization modes, respectively. Two turnovers of the oxygen evolving center (OEC) beyond the modified S2' state are required for the appearance of these signals. The formation of the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi972471c
更新日期:1998-03-03 00:00:00
abstract::The inhibitory effect of phosphorothioate residues, located within one strand of double-stranded DNA, on the hydrolytic activity of the restriction endonuclease EcoRV was investigated. Specific incorporation of a phosphorothioate group at the site of cleavage yielded the sequence 5'-GATsATC-3'. This modified sequence ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00493a008
更新日期:1990-10-16 00:00:00
abstract::The Autographa californica multinucleocapsid nuclear polyhedrosis virus genome contains nine homologous region (hr1, hr1a, hr2, hr2a, hr3, hr4a, hr4b, hr4c, and hr5) sequences that are thought to be involved in viral replication and activation of transcription. Our results show that the 750 bp hr1 sequence is capable ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049953q
更新日期:2004-06-29 00:00:00
abstract::Three unfolding domains in rabbit muscle aldolase destabilized in 3 M urea have been identified from their unfolding rate constants (0.10, 0.036, and 0.0064 min-1). The populations of folded and various, partially unfolded forms were determined by amide hydrogen exchange and mass spectrometry. Results of this study sh...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi972711o
更新日期:1998-05-05 00:00:00
abstract::Gastric parietal cell apical membranes must protect the cell from the extremely low pH and wide variations in osmolality of the gastric juice. To characterize the permeability properties of gastric apical membranes, we have measured passive permeabilities to water, protons, NH3, and small nonelectrolytes of membrane v...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00061a002
更新日期:1993-03-16 00:00:00
abstract::Glucocorticoid (GC) hormones induce apoptosis in T-cell and pre-B-cell acute lymphoblastic leukemia (ALL) cells. Steroid-mediated apoptosis requires a threshold level of the glucocorticoid receptor (GR) protein, and increasing the intracellular GR levels in ALL cells would augment their hormone sensitivity. A protein ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi1007723
更新日期:2010-10-19 00:00:00
abstract::The structure of the anti-inflammatory drug diclofenac bound in the active site of rabbit microsomal cytochrome P450 2C5/3LVdH was determined by X-ray crystallography to 2.1 A resolution. P450 2C5/3LVdH and the related enzyme 2C5dH catalyze the 4'-hydroxylation of diclofenac with apparent K(m) values of 80 and 57 micr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034556l
更新日期:2003-08-12 00:00:00
abstract::Many early investigations on triple helices have been devoted to the study of the triplex formed by dT*dA-dT base triplets in which the third strand is oriented parallel to the dA strand. We now describe an intramolecular triple helix with dT*dA-dT base triplets in which the pyrimidine third strand is oriented antipar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00045a023
更新日期:1995-11-14 00:00:00
abstract::Monoamine oxidase (MAO) was shown previously [Silverman, R. B., & Hoffman, S. J. (1980) J. Am. Chem. Soc. 102, 7126-7128] to catalyze the oxidation of N-cyclopropylbenzylamine (N-CBA) at two sites on the molecule. Oxidation at the benzyl methylene gave benzaldehyde and cyclopropylamine; oxidation of the cyclopropyl gr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00317a019
更新日期:1984-10-23 00:00:00