Chemical modification of prostaglandin H synthase with diethyl pyrocarbonate.


:The role of histidine in catalysis by prostaglandin H synthase has been investigated using chemical modification with diethyl pyrocarbonate (DEPC), an agent that has been found to rather selectively derivatize histidine residues in proteins under mild conditions. Incubation of the synthase apoprotein with DEPC at pH 7.2 resulted in a progressive loss of the capacity for both cyclooxygenase and peroxidase catalytic activities. The kinetics of inactivation of the cyclooxygenase activity were dependent on the concentration of DEPC; a second-order rate constant of 680 M-1 min-1 was estimated for reaction of the apoenzyme at pH 7.2 and 0 degrees C. The kinetics of inactivation of the cyclooxygenase by DEPC exhibited a sigmoidal dependence on the pH, indicating that deprotonation of a group with a pKa of 6.3 was required for inactivation. The presence of the heme prosthetic group slowed, but did not prevent, inactivation by DEPC. The stoichiometry of histidine modification of apoenzyme during inactivation determined from absorbance increases at 242 nm agreed well with the overall stoichiometry of derivatized residues determined with [14C]DEPC, indicating that modification by DEPC was quite selective for histidine residues on the synthase. Although modification of several histidine residues by DEPC was observed, only one of the histidine residues was essential for cyclooxygenase activity. Modification of the holoenzyme with DEPC altered the EPR signal of the hydroperoxide-induced tyrosyl free radical from the wide doublet (35 G, peak-to-trough) found with the native synthase to a narrower singlet (28 G, peak-to-trough) quite like that found in the indomethacin-synthase complex. Reaction of the indomethacin-synthase complex with DEPC was found to increase the cyclooxygenase velocity by 9 times its initial value, to about one-third of the uninhibited value, without displacement of the indomethacin; the peroxidase was significantly inactivated under the same conditions. Histidyl residues in the synthase are thus likely to have important roles not only in cyclooxygenase and peroxidase catalysis but also in the interaction of the synthase with indomethacin.






Zhang X,Tsai AL,Kulmacz RJ




Has Abstract


1992-03-10 00:00:00












  • Binding and recognition of GATATC target sequences by the EcoRV restriction endonuclease: a study using fluorescent oligonucleotides and fluorescence polarization.

    abstract::Oligonucleotides labeled with hexachlorofluorescein (hex) have enabled the interaction of the restriction endonuclease EcoRV with DNA to be evaluated using fluorescence anisotropy. The sensitivity of hex allowed measurements at oligonucleotide concentrations as low as 1 nM, enabling K(D) values in the low nanomolar ra...


    pub_type: 杂志文章


    authors: Reid SL,Parry D,Liu HH,Connolly BA

    更新日期:2001-02-27 00:00:00

  • Enhanced processivity of nuclear matrix bound DNA polymerase alpha from regenerating rat liver.

    abstract::Translocation of DNA during in vitro DNA synthesis on nuclear matrix bound replicational assemblies from regenerating rat liver was determined by measuring the processivity (average number of nucleotides added following one productive binding event of the polymerase to the DNA template) of nuclear matrix bound DNA pol...


    pub_type: 杂志文章


    authors: Tubo RA,Martelli AM,Berezney R

    更新日期:1987-09-08 00:00:00

  • Structural RNA mimetics: N3'-->P5' phosphoramidate DNA analogs of HIV-1 RRE and TAR RNA form A-type helices that bind specifically to Rev and Tat-related peptides.

    abstract::An attractive strategy for the development of anti-retroviral drugs is the exploration of compounds that mimic RNA control regions of the viral genome and act as "decoys" to sequester viral gene regulatory proteins. Decoys consisting of RNA, however, are chemically unstable and readily degraded by cellular nucleases. ...


    pub_type: 杂志文章


    authors: Rigl CT,Lloyd DH,Tsou DS,Gryaznov SM,Wilson WD

    更新日期:1997-01-21 00:00:00

  • The difference in the binding of phosphatidylinositol distinguishes MAP2 from MAP2C and Tau.

    abstract::The interactions of bovine brain MAP2 and tau, recombinant murine MAP2C, and recombinant human tau with phosphatidylinositol vesicles yield apparent Kd values of 51 +/- 6 nM, 2.4 +/- 0.6 microM, 1.4 +/- 0.1 microM, and 1.6 +/- 0.2 microM, respectively. Examinations of the binding of MAP2 and/or MAP2C to phosphatidylch...


    pub_type: 杂志文章


    authors: Surridge CD,Burns RG

    更新日期:1994-07-05 00:00:00

  • DNA solution conformation via infrared circular dichroism: experimental and theoretical results for B-family polymers.

    abstract::Infrared (vibrational) circular dichroism (VCD) has been observed for the DNA models d(CG)5, poly(dG-dC).poly(dG-dC), poly(dG).poly(dC), poly(dA-dT).poly(dA-dT), and poly(dA).poly(dT) in the B-conformation in buffered, aqueous solution. The observed results are quantitatively interpreted in terms of the exciton model ...


    pub_type: 杂志文章


    authors: Zhong WX,Gulotta M,Goss DJ,Diem M

    更新日期:1990-08-14 00:00:00

  • Evidence for a nucleotide binding site on the isolated beta subunit from Escherichia coli F1-ATPase. Interaction between nucleotide and aurovertin D binding sites.

    abstract::The nucleotide binding capacity and affinity of the isolated beta subunit from Escherichia coli F1-ATPase have been studied with radiolabeled ADP and ATP by an equilibrium dialysis technique. Each mole of beta subunit in the presence of EDTA bound 1 mol of ADP or ATP with Kd values of 25 microM and 50-100 microM, resp...


    pub_type: 杂志文章


    authors: Issartel JP,Vignais PV

    更新日期:1984-12-18 00:00:00

  • Structural and dynamic study of the tetramerization region of non-erythroid alpha-spectrin: a frayed helix revealed by site-directed spin labeling electron paramagnetic resonance.

    abstract::The N-terminal region of alpha-spectrin is responsible for its association with beta-spectrin in a heterodimer, forming functional tetramers. Non-erythroid alpha-spectrin (alphaII-spectrin) has a significantly higher association affinity for beta-spectrin than the homologous erythroid alpha-spectrin (alphaI-spectrin)....


    pub_type: 杂志文章


    authors: Li Q,Fung LW

    更新日期:2009-01-13 00:00:00

  • The structural dynamics of actin during active interaction with myosin depends on the isoform of the essential light chain.

    abstract::We have used time-resolved phosphorescence anisotropy to investigate the effects of essential light chain (ELC) isoforms (A1 and A2) on the interaction of skeletal muscle myosin with actin, to relate structural dynamics to previously reported functional effects. Actin was labeled with a phosphorescent probe at C374, a...


    pub_type: 杂志文章


    authors: Prochniewicz E,Guhathakurta P,Thomas DD

    更新日期:2013-03-05 00:00:00

  • A mechanism for reducing entropic cost of induced fit in protein--RNA recognition.

    abstract::Induced fit has been postulated to be an important component of ligand interactions with proteins, including protein-DNA interactions. We imagined that the entropic cost of induced fit might be highly dependent on the local protein sequence context around critical contact residues. To investigate this question, we ana...


    pub_type: 杂志文章


    authors: Ribas de Pouplana L,Auld DS,Kim S,Schimmel P

    更新日期:1996-06-25 00:00:00

  • Computational Study of Binding of μ-Conotoxin GIIIA to Bacterial Sodium Channels NaVAb and NaVRh.

    abstract::Structures of several voltage-gated sodium (NaV) channels from bacteria have been determined recently, but the same feat might not be achieved for the mammalian counterparts in the near future. Thus, at present, computational studies of the mammalian NaV channels have to be performed using homology models based on the...


    pub_type: 杂志文章


    authors: Patel D,Mahdavi S,Kuyucak S

    更新日期:2016-03-29 00:00:00

  • Detailed kinetic analysis of a family 52 glycoside hydrolase: a beta-xylosidase from Geobacillus stearothermophilus.

    abstract::Geobacillus stearothermophilus T-6 encodes for a beta-xylosidase (XynB2) from family 52 of glycoside hydrolases that was previously shown to hydrolyze its substrate with net retention of the anomeric configuration. XynB2 significantly prefers substrates with xylose as the glycone moiety and exhibits a typical bell-sha...


    pub_type: 杂志文章


    authors: Bravman T,Zolotnitsky G,Belakhov V,Shoham G,Henrissat B,Baasov T,Shoham Y

    更新日期:2003-09-09 00:00:00

  • The intrinsic protein flexibility of endogenous protease inhibitor TIMP-1 controls its binding interface and affects its function.

    abstract::Protein flexibility is thought to play key roles in numerous biological processes, including antibody affinity maturation, signal transduction, and enzyme catalysis, yet only limited information is available regarding the molecular details linking protein dynamics with function. A single point mutation at the distal s...


    pub_type: 杂志文章


    authors: Grossman M,Tworowski D,Dym O,Lee MH,Levy Y,Murphy G,Sagi I

    更新日期:2010-07-27 00:00:00

  • Structural similarities and differences among metal ion complexes of phosphoglucomutase by solvent perturbation and ultraviolet difference spectroscopy.

    abstract::Although the binding of bivalent metal-ion activators to phosphoglucomutase produces substantial changes in the near ultraviolet spectrum of the enzyme, the extent to which aromatic residues are exposed to the aqueous environment, as assessed by means of solvent perturbation spectroscopy (using D2O), does not appear t...


    pub_type: 杂志文章


    authors: Ray WJ Jr

    更新日期:1978-04-18 00:00:00

  • Isoforms of the EP3 subtype of human prostaglandin E2 receptor transduce both intracellular calcium and cAMP signals.

    abstract::The EP3 subtype of prostaglandin E2 receptor transduces diverse physiological responses in mammalian tissues through signaling pathways coupled to heterotrimeric G proteins. Distinct cDNA clones encoding five isoforms of the EP3 receptor were isolated from a human uterus cDNA library. The human EP3 receptor isoforms d...


    pub_type: 杂志文章


    authors: An S,Yang J,So SW,Zeng L,Goetzl EJ

    更新日期:1994-12-06 00:00:00

  • Gene structure and chromosomal localization of plasma kallikrein.

    abstract::Plasma kallikrein (Fletcher factor) is a hepatic serine proteinase that participated in the early phase of blood coagulation. From two genomic libraries, we succeeded to isolate four overlapping clones representing the entire rat plasma kallikrein gene. Using selective DNA sequencing, polymerase chain reactions, and r...


    pub_type: 杂志文章


    authors: Beaubien G,Rosinski-Chupin I,Mattei MG,Mbikay M,Chrétien M,Seidah NG

    更新日期:1991-02-12 00:00:00

  • Local destabilization of the metal-binding region in human copper-zinc superoxide dismutase by remote mutations is a possible determinant for progression of ALS.

    abstract::More than 100 distinct mutations in the gene CuZnSOD encoding human copper-zinc superoxide dismutase (CuZnSOD) have been associated with familial amyotrophic lateral sclerosis (fALS), a fatal neuronal disease. Many studies of different mutant proteins have found effects on protein stability, catalytic activity, and me...


    pub_type: 杂志文章


    authors: Hennig J,Andrésen C,Museth AK,Lundström P,Tibell LA,Jonsson BH

    更新日期:2015-01-20 00:00:00

  • Influence of sequence-dependent cytosine protonation and methylation on DNA triplex stability.

    abstract::To investigate cytosine protonation and its influence on the sequence-dependent thermal stability of DNA triplexes in detail, we have employed homo- and heteronuclear NMR experiments on specifically (15)N-labeled oligodeoxynucleotides that were designed to fold into intramolecular triple helices of the pyrimidine moti...


    pub_type: 杂志文章


    authors: Leitner D,Schröder W,Weisz K

    更新日期:2000-05-16 00:00:00

  • Structure and polymorphism of saturated monoacid 1,2-diacyl-sn-glycerols.

    abstract::The 1,2-diacyl-sn-glycerols (1,2-DGs) are the predominant naturally occurring isomer found in cell membranes, lipid droplets, and lipoproteins. They are involved in the metabolism of monoacylglycerols, triacylglycerols, and phospholipids. The 1,2-DGs participate in the activation of protein kinase C, in phosphorylatio...


    pub_type: 杂志文章


    authors: Kodali DR,Fahey DA,Small DM

    更新日期:1990-12-04 00:00:00

  • Structural Elucidation of Peptide Binding to KLHL-12, a Substrate Specific Adapter Protein in a Cul3-Ring E3 Ligase Complex.

    abstract::KLHL-12 is a substrate specific adapter protein for a Cul3-Ring ligase complex. It is a member of the Kelch β-propeller domain subclass of Cullin-Ring substrate recognition domains. This E3 ubiquitin ligase complex has many activities, including acting as a negative regulator of the Wnt signaling pathway by mediating ...


    pub_type: 杂志文章


    authors: Zhao B,Payne WG,Sai J,Lu Z,Olejniczak ET,Fesik SW

    更新日期:2020-03-03 00:00:00

  • Interfacial catalysis by phospholipase A2: the rate-limiting step for enzymatic turnover.

    abstract::The kinetics of the phospholipase A2-catalyzed hydrolysis of bilayer vesicles and mixed micelles of several oxyglycero and thioglycero analogues of phospholipids have been studied. The results with vesicles show that, depending on the source of the enzyme, the rates of hydrolysis of the oxy-containing long-chain phosp...


    pub_type: 杂志文章


    authors: Jain MK,Yu BZ,Rogers J,Gelb MH,Tsai MD,Hendrickson EK,Hendrickson HS

    更新日期:1992-09-01 00:00:00

  • L30A Mutation of Phospholemman Mimics Effects of Cardiac Glycosides in Isolated Cardiomyocytes.

    abstract::To determine if mutations introduced into phospholemman (PLM) could increase the level of PLM-Na,K-ATPase (NKA) binding, we performed scanning mutagenesis of the transmembrane domain of PLM and measured Förster resonance energy transfer (FRET) between each mutant and NKA. We observed an increased level of binding to N...


    pub_type: 杂志文章


    authors: Himes RD,Smolin N,Kukol A,Bossuyt J,Bers DM,Robia SL

    更新日期:2016-11-08 00:00:00

  • Stabilizing and Understanding a Miniprotein by Rational Redesign.

    abstract::Miniproteins reduce the complexity of the protein-folding problem allowing systematic studies of contributions to protein folding and stabilization. Here, we describe the rational redesign of a miniprotein, PPα, comprising a polyproline II helix, a loop, and an α helix. The redesign provides a de novo framework for in...


    pub_type: 杂志文章


    authors: Porter Goff KL,Nicol D,Williams C,Crump MP,Zieleniewski F,Samphire JL,Baker EG,Woolfson DN

    更新日期:2019-07-16 00:00:00

  • Neuronal Synapses: Microscale Signal Processing Machineries Formed by Phase Separation?

    abstract::The organization principles underlying non-membrane-bound organelles have started to unravel in the past 10 years. A new biophysical model known as biomolecular condensates has been proposed to explain many aspects of membraneless organelle assembly and regulation. Neurons are extremely complex, and each neuron can co...


    pub_type: 杂志文章,评审


    authors: Feng Z,Zeng M,Chen X,Zhang M

    更新日期:2018-05-01 00:00:00

  • β-Lactone Synthetase Found in the Olefin Biosynthesis Pathway.

    abstract::The first β-lactone synthetase enzyme is reported, creating an unexpected link between the biosynthesis of olefinic hydrocarbons and highly functionalized natural products. The enzyme OleC, involved in the microbial biosynthesis of long-chain olefinic hydrocarbons, reacts with syn- and anti-β-hydroxy acid substrates t...


    pub_type: 杂志文章


    authors: Christenson JK,Richman JE,Jensen MR,Neufeld JY,Wilmot CM,Wackett LP

    更新日期:2017-01-17 00:00:00

  • Characterization and purification of the discoidin domain-containing protein retinoschisin and its interaction with galactose.

    abstract::RS1, also known as retinoschisin, is an extracellular discoidin domain-containing protein that has been implicated in maintaining the cellular organization and synaptic structure of the vertebrate retina. Mutations in the gene encoding RS1 are responsible for X-linked retinoschisis, a retinal degenerative disease char...


    pub_type: 杂志文章


    authors: Dyka FM,Wu WW,Pfeifer TA,Molday LL,Grigliatti TA,Molday RS

    更新日期:2008-09-02 00:00:00

  • Structure of mammalian cytochrome P450 2C5 complexed with diclofenac at 2.1 A resolution: evidence for an induced fit model of substrate binding.

    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...


    pub_type: 杂志文章


    authors: Wester MR,Johnson EF,Marques-Soares C,Dijols S,Dansette PM,Mansuy D,Stout CD

    更新日期:2003-08-12 00:00:00

  • The dimerization domain in outer segment guanylate cyclase is a Ca²⁺-sensitive control switch module.

    abstract::Membrane-bound guanylate cyclases harbor a region called the dimerization or linker domain, which aids the enzymes in adopting an optimal monomer-monomer arrangement for catalysis. One subgroup of these guanylate cyclases is expressed in rod and cone cells of vertebrate retina, and mutations in the dimerization domain...


    pub_type: 杂志文章


    authors: Zägel P,Dell'Orco D,Koch KW

    更新日期:2013-07-30 00:00:00

  • Proton transfer in carbonic anhydrase is controlled by electrostatics rather than the orientation of the acceptor.

    abstract::Combined quantum mechanical/molecular mechanical (QM/MM) simulations are carried out to analyze factors that dictate the proton transfer in carbonic anhydrase II (CAII), an enzyme that has been used as a prototypical example of long-range proton transfers in biomolecules. In contrast to the long-held conjecture in the...


    pub_type: 杂志文章


    authors: Riccardi D,König P,Guo H,Cui Q

    更新日期:2008-02-26 00:00:00

  • Occurrence of 2-5A and RNA degradation in the chick oviduct during rapid estrogen withdrawal.

    abstract::Rapid withdrawal of estrogen from immature chicks, previously stimulated with the hormone, results in the inhibition of transcription of mRNAs of egg white proteins, rapid degradation of existing estrogen-induced mRNAs of egg white proteins, and decline in ribosomes and weight of the oviduct. On rapid withdrawal of es...


    pub_type: 杂志文章


    authors: Cohrs RJ,Goswami BB,Sharma OK

    更新日期:1988-05-03 00:00:00

  • Interaction of human immunodeficiency virus type 1 Tat-derived peptides with TAR RNA.

    abstract::Basic peptides from the carboxy terminus of the human immunodeficiency virus type 1 (HIV-1) Tat protein bind to the stem-loop region of TAR RNA, spanning a trinucleotide bulge, with high affinity and moderate specificity. Previous studies have demonstrated that TAR RNA contains a specific arginine binding pocket. A se...


    pub_type: 杂志文章


    authors: Long KS,Crothers DM

    更新日期:1995-07-11 00:00:00