Mechanism of action of phalloidin on the polymerization of muscle actin.


:Under conditions where muscle actin only partially polymerizes, or where it does not polymerize at all, a significant enhancement of polymerization was observed if equimolar phalloidin was also present. The increased extent of polymerization in the the presence of phalloidin can be explained by the reduced critical actin concentration of partially polymerized populations at equilibrium. Under such conditions, the rate of polymerization, as judged by the length of time to reach half the viscosity plateau, was found to be essentially independent of the phalloidin concentration. Moreover, the initial rate of polymerization of actin was also found to be independent of phalloidin concentration. However, phalloidin apparently causes a reduction in the magnitude of the reverse rates in the polymerization reaction, as was demonstrated by the lack of depolymerization of phalloidin-treated actin polymers. This effect of phalloidin is also supported by the identification of actin nuclei and short polymers in populations of G-actin incubated with phalloidin in the absence of added KCl. Our conclusion, then, is that phalloidin influences the polymerization of actin by stabilizing nuclei and polymers as they are formed.






Estes JE,Selden LA,Gershman LC




Has Abstract


1981-02-17 00:00:00












  • Differential susceptibility of transferrin glycoforms to chymotrypsin: a proteomics approach to the detection of carbohydrate-deficient transferrin.

    abstract::Transferrin exhibits heterogeneity in glycosylation characteristic of pathological changes in alcohol abuse and congenital disorders in glycosylation. This study investigated an alternative approach in the detection of carbohydrate-deficient transferrin based on the premise that glycosylation may afford some degree of...


    pub_type: 杂志文章


    authors: Valmu L,Kalkkinen N,Husa A,Rye PD

    更新日期:2005-12-13 00:00:00

  • HIV-1 membrane fusion mechanism: structural studies of the interactions between biologically-active peptides from gp41.

    abstract::Two synthetic peptides corresponding to sequences in HIV-1LAI gp41, (aa558-595) and T20 (aa 643-678), are strong inhibitors of HIV-1 viral fusion, having EC50 values of 1 microgram/mL and 1 ng/mL, respectively. Previous work suggested that T21 forms a coiled-coil structure in PBS solution, while T20 is primarily nonhe...


    pub_type: 杂志文章


    authors: Lawless MK,Barney S,Guthrie KI,Bucy TB,Petteway SR Jr,Merutka G

    更新日期:1996-10-22 00:00:00

  • Stereospecific Radical-Mediated B12-Dependent Methyl Transfer by the Fosfomycin Biosynthesis Enzyme Fom3.

    abstract::Fom3, the antepenultimate enzyme in the fosfomycin biosynthetic pathway in Streptomyces spp., is a class B cobalamin-dependent radical SAM methyltransferase that catalyzes methylation of (5'-cytidylyl)-2-hydroxyethylphosphonate (2-HEP-CMP) to form (5'-cytidylyl)-2-hydroxypropylphosphonate (2-HPP-CMP). Previously, the ...


    pub_type: 杂志文章


    authors: McLaughlin MI,van der Donk WA

    更新日期:2018-08-21 00:00:00

  • Interaction of tetrahydrofolate and other folate derivatives with bacterial sarcosine oxidase.

    abstract::Sarcosine oxidase from Corynebacterium sp. P-1 binds 2 mol of tetrahydrofolate/mol of enzyme (KD = 8.8 microM). The same stoichiometry is observed with tetrahydropteroyltetraglutamate (KD = 15.4 microM). Binding is also observed with pteroyltetraglutamate and with 5-formyltetrahydrofolate. In the case of the pteroylmo...


    pub_type: 杂志文章


    authors: Kvalnes-Krick K,Jorns MS

    更新日期:1987-11-17 00:00:00

  • Glycosaminoglycans of brain during development.

    abstract::The concentration of hyaluronic acid, chondroitin sulfate, and heparan sulfate was measured in rat brain at 2-day intervals from birth to 1 month of age, and in 40-day-old and adult animals. The levels of all three glycosaminoglycans increased after birth to reach a peak at 7 days after which they declined steadily, a...


    pub_type: 杂志文章


    authors: Margolis RU,Margolis RK,Chang LB,Preti C

    更新日期:1975-01-14 00:00:00

  • Ligand migration and binding in nonsymbiotic hemoglobins of Arabidopsis thaliana.

    abstract::We have studied carbon monoxide (CO) migration and binding in the nonsymbiotic hemoglobins AHb1 and AHb2 of Arabidopsis thaliana using Fourier transform infrared (FTIR) spectroscopy combined with temperature derivative spectroscopy (TDS) at cryogenic temperatures. Both proteins have similar amino acid sequences but di...


    pub_type: 杂志文章


    authors: Nienhaus K,Dominici P,Astegno A,Abbruzzetti S,Viappiani C,Nienhaus GU

    更新日期:2010-09-07 00:00:00

  • A quantitative index of substrate promiscuity.

    abstract::Catalytic promiscuity is a widespread, but poorly understood, phenomenon among enzymes with particular relevance to the evolution of new functions, drug metabolism, and in vitro biocatalyst engineering. However, there is at present no way to quantitatively measure or compare this important parameter of enzyme function...


    pub_type: 杂志文章


    authors: Nath A,Atkins WM

    更新日期:2008-01-08 00:00:00

  • Oligomeric states of the HIV-1 integrase as measured by time-resolved fluorescence anisotropy.

    abstract::Self-assembly properties of HIV-1 integrase were investigated by time-resolved fluorescence anisotropy using tryptophanyl residues as a probe. From simulation analyses, we show that suitable photon counting leads to an accurate determination of long rotational correlation times in the range of 20-80 ns, permitting the...


    pub_type: 杂志文章


    authors: Deprez E,Tauc P,Leh H,Mouscadet JF,Auclair C,Brochon JC

    更新日期:2000-08-08 00:00:00

  • Effect of β,γ-CHF- and β,γ-CHCl-dGTP halogen atom stereochemistry on the transition state of DNA polymerase β.

    abstract::Recently, we synthesized the first individual β,γ-CHX-dGTP diastereomers [(R)- or (S)-CHX, where X is F or Cl] and determined their structures in ternary complexes with DNA polymerase β (pol β). We now report stereospecificity by pol β on the mixed β,γ-CHX diastereomer pairs using nuclear magnetic resonance and on the...


    pub_type: 杂志文章


    authors: Oertell K,Wu Y,Zakharova VM,Kashemirov BA,Shock DD,Beard WA,Wilson SH,McKenna CE,Goodman MF

    更新日期:2012-10-30 00:00:00

  • Efficient repair of 8-oxo-7,8-dihydrodeoxyguanosine in human and hamster xeroderma pigmentosum D cells.

    abstract::The repair of the endogenous lesion 8-oxo-7,8-dihydrodeoxyguanosine (8-oxodG) was investigated in the nucleotide excision repair mutant xeroderma pigmentosum D (XPD), using human normal or transformed XPD fibroblasts and the Chinese hamster XPD cell line UV5. In vivo repair of 8-oxodG induced by hydrogen peroxide trea...


    pub_type: 杂志文章


    authors: Cappelli E,Degan P,Thompson LH,Frosina G

    更新日期:2000-08-29 00:00:00

  • Probing for and Quantifying Agonist Hydrogen Bonds in α6β2 Nicotinic Acetylcholine Receptors.

    abstract::Designing subtype-selective agonists for neuronal nicotinic acetylcholine receptors is a challenging and significant goal aided by intricate knowledge of each subtype's binding patterns. We previously reported that in α6β2 receptors, acetylcholine makes a functional cation-π interaction with Trp149, but nicotine and T...


    pub_type: 杂志文章


    authors: Post MR,Lester HA,Dougherty DA

    更新日期:2017-04-04 00:00:00

  • Affinity labeling of aminoacyl-tRNA synthetases with adenosine triphosphopyridoxal: probing the Lys-Met-Ser-Lys-Ser signature sequence as the ATP-binding site in Escherichia coli methionyl-and valyl-tRNA synthetases.

    abstract::Pyridoxal 5'-triphospho-5'-adenosine (AP3-PL), the affinity labeling reagent specific for lysine residues in the nucleotide-binding site of several enzymes [Tagaya, M., & Fukui, T. (1986) Biochemistry 25, 2958-2964; Yagami, T., Tagaya, M., & Fukui, T. (1988) FEBS Lett. 229, 261-264], was used to identify the ATP-bindi...


    pub_type: 杂志文章


    authors: Hountondji C,Schmitter JM,Fukui T,Tagaya M,Blanquet S

    更新日期:1990-12-25 00:00:00

  • Molecular characterization of the catalytic domains of human complement serine protease C1r.

    abstract::Limited cleavages of human C1r by extrinsic proteases of various specificity (plasmin, elastase, chymotrypsin, thermolysin) yield dimeric associations of two globular domains, each comprised of the intact B chain disulfide linked to gamma, the C-terminal fragment of the A chain. These (gamma-B)2 domains, which are hom...


    pub_type: 杂志文章


    authors: Arlaud GJ,Gagnon J,Villiers CL,Colomb MG

    更新日期:1986-09-09 00:00:00

  • Structural and biochemical studies of a fluoroacetyl-CoA-specific thioesterase reveal a molecular basis for fluorine selectivity.

    abstract::We have initiated a broad-based program aimed at understanding the molecular basis of fluorine specificity in enzymatic systems, and in this context, we report crystallographic and biochemical studies on a fluoroacetyl-coenzyme A (CoA) specific thioesterase (FlK) from Streptomyces cattleya. Our data establish that FlK...


    pub_type: 杂志文章


    authors: Weeks AM,Coyle SM,Jinek M,Doudna JA,Chang MC

    更新日期:2010-11-02 00:00:00

  • Isolation and characterization of titin T1 from bovine cardiac muscle.

    abstract::Methods were developed for isolation of bovine cardiac titin in the apparently full-sized T1 form. The pure protein could be obtained either in the denatured state after chromatography of myofibril extracts on Sephacryl S-1000 or in the native state using hydroxylapatite chromatography. Titin-specific chicken polyclon...


    pub_type: 杂志文章


    authors: Pan KM,Damodaran S,Greaser ML

    更新日期:1994-07-12 00:00:00

  • Studies of inhibitor binding to Escherichia coli purine nucleoside phosphorylase using the transferred nuclear Overhauser effect and rotating-frame nuclear Overhauser enhancement.

    abstract::NMR studies of the adenosine analog tubercidin have been carried out in the presence of Escherichia coli purine nucleoside phosphorylase (PNP) in order to characterize the conformation of the enzyme-complexed nucleoside. Although analysis of transferred NOE data at various enzyme/inhibitor ratios indicated a predomina...


    pub_type: 杂志文章


    authors: Perlman ME,Davis DG,Koszalka GW,Tuttle JV,London RE

    更新日期:1994-06-21 00:00:00

  • Mapping a ketosynthase:acyl carrier protein binding interface via unnatural amino acid-mediated photo-cross-linking.

    abstract::Probing and interrogating protein interactions that involve acyl carrier proteins (ACP's) in fatty acid synthases and polyketide synthases are critical to understanding the molecular basis for the programmed assembly of complex natural products. Here, we have used unnatural amino acid mutagenesis to site specifically ...


    pub_type: 杂志文章


    authors: Ye Z,Williams GJ

    更新日期:2014-12-09 00:00:00

  • Functional role of the conserved active site proline of triosephosphate isomerase.

    abstract::The importance of the fully conserved active site proline, Pro168, for the reaction mechanism of triosephosphate isomerase (TIM) has been investigated by studying the enzymatic and crystallographic properties of the P168A variant of trypanosomal TIM. In TIM, Pro168 follows the key catalytic residue Glu167, situated at...


    pub_type: 杂志文章


    authors: Casteleijn MG,Alahuhta M,Groebel K,El-Sayed I,Augustyns K,Lambeir AM,Neubauer P,Wierenga RK

    更新日期:2006-12-26 00:00:00

  • Ligand-free open-closed transitions of periplasmic binding proteins: the case of glutamine-binding protein.

    abstract::The ability to undergo large-scale domain rearrangements is essential for the substrate-binding function of periplasmic binding proteins (PBPs), which are indispensable for nutrient uptake in Gram-negative bacteria. Crystal structures indicate that PBPs typically adopt either an "open" unliganded configuration or a "c...


    pub_type: 杂志文章


    authors: Bermejo GA,Strub MP,Ho C,Tjandra N

    更新日期:2010-03-09 00:00:00

  • Molecular dynamics simulations of pentapeptides at interfaces: salt bridge and cation-pi interactions.

    abstract::Peptide-membrane interactions are important for understanding the binding, partitioning, and folding of membrane proteins; the activity of antimicrobial and fusion peptides; and a number of other processes. We describe molecular dynamics simulations (10-25 ns) of two pentapeptides Ace-WLXLL (with X = Arg or Lys side c...


    pub_type: 杂志文章


    authors: Aliste MP,MacCallum JL,Tieleman DP

    更新日期:2003-08-05 00:00:00

  • Kinetics of calcium uptake by isolated sarcoplasmic reticulum vesicles using flash photolysis of caged adenosine 5'-triphosphate.

    abstract::The kinetics of ATP-induced Ca2+ uptake by vesicular dispersions of sarcoplasmic reticulum were determined with a time resolution of about 10 ms, depending on the temperature. Ca2+ uptake was initiated by the addition of ATP through the flash photolysis of P3-1-(2-nitrophenyl)-ethyl adenosine 5'-triphosphate utilizing...


    pub_type: 杂志文章


    authors: Pierce DH,Scarpa A,Topp MR,Blasie JK

    更新日期:1983-11-08 00:00:00

  • Stereochemistry of phospho group transfer catalyzed by a mutant alkaline phosphatase.

    abstract::The stereochemical course of the phospho group transfer catalyzed by mutant (S102C) alkaline phosphatase from Escherichia coli was investigated by using 31P nuclear magnetic resonance spectroscopy. Transphosphorylation from 4-nitrophenyl (Rp)-[16O, 17O, 18O]phosphate to (S)-propane-1,2-diol occurs with overall retenti...


    pub_type: 杂志文章


    authors: Butler-Ransohoff JE,Kendall DA,Freeman S,Knowles JR,Kaiser ET

    更新日期:1988-06-28 00:00:00

  • Purification and characterization of two unique forms of cytochrome P-450 from rabbit nasal microsomes.

    abstract::Two forms of cytochrome P-450, designated P-450NMa and P-450NMb, were purified to electrophoretic homogeneity from rabbit nasal microsomes. The purified cytochromes, which contained 14-16 nmol of P-450/mg of protein, exhibited apparent monomeric molecular weights of 49,500 and 51,000, respectively. As indicated by sev...


    pub_type: 杂志文章


    authors: Ding XX,Coon MJ

    更新日期:1988-11-01 00:00:00

  • Deuterium kinetic isotope effects and the mechanism of the bacterial luciferase reaction.

    abstract::A combined experimental and theoretical investigation of the deuterium isotope effects on the bacterial luciferase reaction is described. The experimental studies focus on determining if the unusual aldehydic deuterium isotope effect of approximately 1.5 observed in these reactions is an intrinsic isotope effect resul...


    pub_type: 杂志文章


    authors: Francisco WA,Abu-Soud HM,DelMonte AJ,Singleton DA,Baldwin TO,Raushel FM

    更新日期:1998-02-24 00:00:00

  • Steps toward constructing a cytochrome b6 f complex in the purple bacterium Rhodobacter sphaeroides: an example of the structural plasticity of a membrane cytochrome.

    abstract::We have modified the cytochrome b subunit of the cytochrome bc1 complex from the purple bacterium Rhodobacter sphaeroides to introduce two distinctive features of cytochrome b6 f complexes. In the first one, we have split cyt b into two polypeptides thus mimicking the organization of cyt b6 and subunit IV in the b6 f ...


    pub_type: 杂志文章


    authors: Kuras R,Guergova-Kuras M,Crofts AR

    更新日期:1998-11-17 00:00:00

  • A conformational change in the human major histocompatibility complex protein HLA-DR1 induced by peptide binding.

    abstract::To investigate a conformational change accompanying peptide binding to class II MHC proteins, we probed the structure of a soluble version of the human class II MHC protein HLA-DR1 in empty and peptide-loaded forms. Peptide binding induced a large decrease in the effective radius of the protein as determined by gel fi...


    pub_type: 杂志文章


    authors: Zarutskie JA,Sato AK,Rushe MM,Chan IC,Lomakin A,Benedek GB,Stern LJ

    更新日期:1999-05-04 00:00:00

  • Nuclear deoxyribonucleic acid characterization of the marine chromophyte Olisthodiscus luteus.

    abstract::Nuclear DNA of the marine chromophytic alga Olisthodiscus luteus was analyzed in this study. Reassociation kinetics analysis has shown that 440-nucleotide DNA fragments from the genome of this alga contain 4% foldback, 58% repetitive, and 34% single-copy sequences. Precise analysis using isolated single-copy DNA revea...


    pub_type: 杂志文章


    authors: Ersland DR,Cattolico RA

    更新日期:1981-11-24 00:00:00

  • Is Arg418 the catalytic base required for the hydrolysis step of the IMP dehydrogenase reaction?

    abstract::The first committed step of guanine nucleotide biosynthesis is the oxidation of inosine 5'-monophosphate (IMP) to xanthosine 5'-monophosphate (XMP) catalyzed by IMP dehydrogenase. The reaction involves the reduction of NAD(+) with the formation of a covalent enzyme intermediate (E-XMP). Hydrolysis of E-XMP requires th...


    pub_type: 杂志文章


    authors: Guillén Schlippe YV,Hedstrom L

    更新日期:2005-09-06 00:00:00

  • Influence of the extent of branching on solution conformations of complex oligosaccharides: a molecular dynamics and NMR study of a penta-antennary "bisected" N-glycan.

    abstract::The solution conformation of an agalactosyl penta-antennary "bisected" N-linked glycan from hen ovomucoid has been determined using a combination of 1H-NMR NOE measurements and restrained molecular dynamics (MD) simulations. The majority of glycosidic linkages exhibited restricted torsional fluctuations about the glob...


    pub_type: 杂志文章


    authors: Rutherford TJ,Neville DC,Homans SW

    更新日期:1995-10-31 00:00:00

  • Spectroscopic studies of quinonoid species from pyridoxal 5'-phosphate.

    abstract::To establish the state of protonation of quinonoid species formed nonenzymically from pyridoxal phosphate (PLP) and diethyl aminomalonate, we have studied absorption spectra of the rapidly established steady-state mixture of species. We have evaluated the formation constant and the spectrum of the mixture of Schiff ba...


    pub_type: 杂志文章


    authors: Metzler CM,Harris AG,Metzler DE

    更新日期:1988-06-28 00:00:00