Determination of the rate and yield of B-side quinone reduction in Rhodobacter capsulatus reaction centers.


:In the native purple bacterial reaction center (RC), light-driven charge separation utilizes only the A-side cofactors, with the symmetry related B-side inactive. The process is initiated by electron transfer from the excited primary donor (P*) to the A-side bacteriopheophytin (P* --> P+ H(A)-) in approximately 3 ps. This is followed by electron transfer to the A-side quinone (P+ H(A)- --> P+ Q(A)-) in approximately 200 ps, with an overall quantum yield of approximately 100%. Using nanosecond flash photolysis and RCs from the Rhodobacter capsulatus F(L181)Y/Y(M208)F/L(M212)H mutant (designated YFH), we have probed the decay pathways of the analogous B-side state P+ H(B)-. The rate of the P+ H(B)- --> ground-state charge-recombination process is found to be (3.0 +/- 0.8 ns)(-1), which is much faster than the analogous (10-20 ns)(-1) rate of P+ H(A)- --> ground state. The rate of P+ H(B)- --> P+ Q(B)- electron transfer is determined to be (3.9 +/- 0.9 ns)(-1), which is about a factor of 20 slower than the analogous A-side process P+ H(A)- --> P+ Q(A)-. The yield of P+ H(B)- --> P+ Q(B)- electron-transfer calculated from these rate constants is 44%. This value, when combined with the known 30% yield of P+ H(B)- from P in YFH RCs, gives an overall yield of 13% for B-side charge separation P* --> P+ H(B)- --> P+ Q(B)- in this mutant. We determine essentially the same value (15%) by comparing the P-bleaching amplitude at approximately 1 ms in YFH and wild-type RCs.






Kee HL,Laible PD,Bautista JA,Hanson DK,Holten D,Kirmaier C




Has Abstract


2006-06-13 00:00:00












  • Characterization of large peptide fragments derived from the N-terminal domain of the ribosomal protein L9: definition of the minimum folding motif and characterization of local electrostatic interactions.

    abstract::A set of peptides derived from the N-terminal domain of the ribosomal protein L9 (NTL9) have been characterized in an effort to define the minimum unit of this domain required to fold and to provide model peptides for the analysis of electrostatic interactions in the unfolded state. NTL9 is a 56-residue alpha-beta pro...


    pub_type: 杂志文章


    authors: Horng JC,Moroz V,Rigotti DJ,Fairman R,Raleigh DP

    更新日期:2002-11-12 00:00:00

  • Ataxin-3 is a multivalent ligand for the parkin Ubl domain.

    abstract::The ubiquitin signaling pathway consists of hundreds of enzymes that are tightly regulated for the maintenance of cell homeostasis. Parkin is an E3 ubiquitin ligase responsible for conjugating ubiquitin onto a substrate protein, which itself can be ubiquitinated. Ataxin-3 performs the opposing function as a deubiquiti...


    pub_type: 杂志文章


    authors: Bai JJ,Safadi SS,Mercier P,Barber KR,Shaw GS

    更新日期:2013-10-22 00:00:00

  • A glutamic acid specific serine protease utilizes a novel histidine triad in substrate binding.

    abstract::Proteases specific for cleavage after acidic residues have been implicated in several disease states, including epidermolysis, inflammation, and viral processing. A serine protease with specificity toward glutamic acid substrates (Glu-SGP) has been crystallized in the presence of a tetrapeptide ligand and its structur...


    pub_type: 杂志文章


    authors: Nienaber VL,Breddam K,Birktoft JJ

    更新日期:1993-11-02 00:00:00

  • Heme speciation in alkaline ferric FixL and possible tyrosine involvement in the signal transduction pathway for regulation of nitrogen fixation.

    abstract::The pH-dependent behavior of the ferric forms of two soluble truncations of Rhizobium meliloti FixL, FixL (heme and kinase domains, functional), and FixLN (heme domain) are examined by UV-visible, resonance Raman, and electron paramagnetic resonance spectroscopy. Global analysis of UV-visible data indicates that the p...


    pub_type: 杂志文章


    authors: Lukat-Rodgers GS,Rexine JL,Rodgers KR

    更新日期:1998-09-29 00:00:00

  • Organization of clusters and internal electron pathways in CO dehydrogenase from Clostridium thermoaceticum: relevance to the mechanism of catalysis and cyanide inhibition.

    abstract::Cyanide inhibits the CO oxidation activity of carbon monoxide dehydrogenase from Clostridium thermoaceticum by binding tightly to the form of the C-cluster yielding the gav = 1.82 signal (the C1.82 form). CN- dissociates and the enzyme reactivates upon addition of CO, CO2 plus dithionite, or CS2 plus dithionite. Dithi...


    pub_type: 杂志文章


    authors: Anderson ME,Lindahl PA

    更新日期:1994-07-26 00:00:00

  • Low-temperature solid-state 13C NMR studies of the retinal chromophore in rhodopsin.

    abstract::Magic angle sample spinning (MASS) 13C NMR spectra have been obtained of bovine rhodopsin regenerated with retinal prosthetic groups isotopically enriched with 13C at C-5 and C-14. In order to observe the 13C retinal chromophore resonances, it was necessary to employ low temperatures (-15-----35 degrees C) to restrict...


    pub_type: 杂志文章


    authors: Smith SO,Palings I,Copié V,Raleigh DP,Courtin J,Pardoen JA,Lugtenburg J,Mathies RA,Griffin RG

    更新日期:1987-03-24 00:00:00

  • The limits of promiscuity: isoform-specific dimerization of filamins.

    abstract::Filamins are a family of actin cross-linking proteins that are primarily localized in the cortical cytoplasm of all mammalian cells. Until now, three major isoforms (filamins a, b, and c) have been identified, that were shown to be differentially expressed and/or localized in different tissues. An amino-terminal doubl...


    pub_type: 杂志文章


    authors: Himmel M,Van Der Ven PF,Stöcklein W,Fürst DO

    更新日期:2003-01-21 00:00:00

  • In the sense of transcription regulation by G-quadruplexes: asymmetric effects in sense and antisense strands.

    abstract::G-Quadruplexes occupy important regulatory regions in the genome. DNA G-quadruplexes in the promoter regions and RNA quadruplexes in the UTRs (untranslated regions) have been individually studied and variously implicated at different regulatory levels of gene expression. However, the formation of G-quadruplexes in the...


    pub_type: 杂志文章


    authors: Agarwal T,Roy S,Kumar S,Chakraborty TK,Maiti S

    更新日期:2014-06-17 00:00:00

  • Kinetics of halide release of haloalkane dehalogenase: evidence for a slow conformational change.

    abstract::Haloalkane dehalogenase converts haloalkanes to their corresponding alcohols and halides. The reaction mechanism involves the formation of a covalent alkyl-enzyme complex which is hydrolyzed by water. The active site is a hydrophobic cavity buried between the main domain and the cap domain of the enzyme. The enzyme ha...


    pub_type: 杂志文章


    authors: Schanstra JP,Janssen DB

    更新日期:1996-05-07 00:00:00

  • Biochemical characterization and crystallographic structure of an Escherichia coli protein from the phosphotriesterase gene family.

    abstract::Phosphotriesterase homology protein (PHP) is a member of a recently discovered family of proteins related to phosphotriesterase, a hydrolytic, bacterial enzyme with an unusual substrate specificity for synthetic organophosphate triesters and phosphorofluoridates, which are common constituents of chemical warfare agent...


    pub_type: 杂志文章


    authors: Buchbinder JL,Stephenson RC,Dresser MJ,Pitera JW,Scanlan TS,Fletterick RJ

    更新日期:1998-04-14 00:00:00

  • Critical nature of a specific uridine O2-carbonyl for cleavage by the hammerhead ribozyme.

    abstract::Three modified hammerhead ribozyme/substrate complexes have been prepared in which individual uridine O2-carbonyls have been eliminated. The modified complexes were chemically synthesized with the substitution of a single 2-pyridone (2P) base analogue for residues U4, U7, and U16.1. Steady-state kinetic analyses indic...


    pub_type: 杂志文章


    authors: Bevers S,Ha SB,McLaughlin LW

    更新日期:1999-06-15 00:00:00

  • Effects of replacement of a double bond by a cyclopropane ring in phosphatidylethanolamines: a 2H NMR study of phase transitions and molecular organization.

    abstract::The thermotropic behavior and molecular properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-dihydrosterculoyl-sn-glycero-3-phosphoethanolamine (PDSPE) have been investigated by 2H NMR spectroscopy using samples selectively labeled at the 5'-, 9'-, 10'-, and 16'-positions of the...


    pub_type: 杂志文章


    authors: Perly B,Smith IC,Jarrell HC

    更新日期:1985-02-12 00:00:00

  • An aggregation-prone intermediate species is present in the unfolding pathway of the monomeric portal protein of bacteriophage P22: implications for portal assembly.

    abstract::The head of the P22 bacteriophage is interrupted by a unique dodecameric portal vertex that serves as a conduit for the entrance and exit of the DNA. Here, the in vitro unfolding/refolding processes of the portal protein of P22 were investigated at different temperatures (1, 25, and 37 degrees C) through the use of ur...


    pub_type: 杂志文章


    authors: Braga CA,Carvalho D,Lara FA,Cortines JR,Moore SD,Prevelige PE Jr,Foguel D

    更新日期:2007-06-26 00:00:00

  • Positive and negative hepatic regulation of the human type II phospholipase A2 gene.

    abstract::To identify the elements which regulate the liver transcription of the human type II phospholipase A2 gene and its stimulation by interleukin 6, the 5' flanking region from -1614 to +806 and several 3' and 5' deleted fragments have been analyzed in CAT assays. Negative regulatory elements have been located in the regi...


    pub_type: 杂志文章


    authors: Olivier JL,Fan Q,Salvat C,Ziari M,Kong L,Mangeney M,Bereziat G

    更新日期:1994-06-14 00:00:00

  • Studies of early events of folding of a predominately β-sheet protein using fluorescence correlation spectroscopy and other biophysical methods.

    abstract::The interplay between the early collapse of the unfolded state and the formation of the secondary structure has been the subject of extensive research in protein chemistry. In this study, we used the intestinal fatty acid binding protein (IFABP), a small model protein with predominately β-sheet structure, to study the...


    pub_type: 杂志文章


    authors: Sarkar S,Chattopadhyay K

    更新日期:2014-03-11 00:00:00

  • Structural polymorphism and dynamism in the DNA segment GATCTTCCCCCCGGAA: NMR investigations of hairpin, dumbbell, nicked duplex, parallel strands, and i-motif.

    abstract::Structure and dynamism in a DNA segment d-GATCTTCCCCCCGGAA have been investigated by nuclear magnetic resonance (NMR) spectroscopy. At neutral pH, the molecule exists largely as a dumbbell, formed by the association of two hairpins with sticky ends. A small percentage of hairpin is also detectable. The stem of the dum...


    pub_type: 杂志文章


    authors: Singh S,Patel PK,Hosur RV

    更新日期:1997-10-28 00:00:00

  • Interfacial and lipid transfer properties of human phospholipid transfer protein: implications for the transfer mechanism of phospholipids.

    abstract::In circulation the phospholipid transfer protein (PLTP) facilitates the transfer of phospholipid-rich surface components from postlipolytic chylomicrons and very low density lipoproteins (VLDL) to HDL and thereby regulates plasma HDL levels. To study the molecular mechanisms involved in PLTP-mediated lipid transfer, w...


    pub_type: 杂志文章


    authors: Setälä NL,Holopainen JM,Metso J,Wiedmer SK,Yohannes G,Kinnunen PK,Ehnholm C,Jauhiainen M

    更新日期:2007-02-06 00:00:00

  • pH-dependent charge equilibria between tyrosine-D and the S states in photosystem II. Estimation of relative midpoint redox potentials.

    abstract::The effect of protonation events on the charge equilibrium between tyrosine-D and the water-oxidizing complex in photosystem II has been studied by time-resolved measurements of the EPR signal IIslow at room temperature. The flash-induced oxidation of YD by the water-oxidizing complex in the S2 state is a monophasic p...


    pub_type: 杂志文章


    authors: Vass I,Styring S

    更新日期:1991-01-22 00:00:00

  • Adenosine 5'-(gamma-thiotriphosphate): an ATP analog that should be used with caution in muscle contraction studies.

    abstract::The slowly hydrolyzed ATP analog adenosine 5'-(gamma-thiotriphosphate) (ATP gamma S) has been used in many studies of the muscle motor protein myosin in order to form a stable "weak binding" state analogous to the actin-S1-ATP complex However, the results from studies using ATP gamma S do not always agree with the res...


    pub_type: 杂志文章


    authors: Resetar AM,Chalovich JM

    更新日期:1995-12-12 00:00:00

  • Photoinactivation of peptide transport in Saccharomyces cerevisiae.

    abstract::Oligopeptides and dipeptides are transported into Saccharomyces cerevisiae by a carrier-mediated system. In the dark, leucyl-p-nitroanilide (Leu-p-NA) and leucyl-leucyl-4-azido-2-nitrophenylalanine [Leu-Leu-Phe-(4N3,2NO2)] are competitive inhibitors of peptide transport by S. cerevisiae cells. The photolysis of yeast ...


    pub_type: 杂志文章


    authors: Becker JM,Dunsmore KP,Steinfeld AS,Naider F

    更新日期:1982-11-09 00:00:00

  • Oligonucleotide site directed mutagenesis of all histidine residues within the T4 endonuclease V gene: role in enzyme-nontarget DNA binding.

    abstract::In order to evaluate the contributions that histidine residues might play both in the catalytic activities of endonuclease V and in binding to nontarget DNA, the technique of oligonucleotide site directed mutagenesis was used to create mutations at each of the four histidine residues in the endonuclease V gene. Althou...


    pub_type: 杂志文章


    authors: Augustine ML,Hamilton RW,Dodson ML,Lloyd RS

    更新日期:1991-08-13 00:00:00

  • Volumetrically Derived Thermodynamic Profile of Interactions of Urea with a Native Protein.

    abstract::We report the first experimental characterization of the full thermodynamic profile for binding of urea to a native protein. We measured the volumetric parameters of lysozyme at pH 7.0 as a function of urea within a temperature range of 18-45 °C. At neutral pH, lysozyme retains its native conformation between 0 and 8 ...


    pub_type: 杂志文章


    authors: Son I,Chalikian TV

    更新日期:2016-11-29 00:00:00

  • Molecular mechanism of action of β-hairpin antimicrobial peptide arenicin: oligomeric structure in dodecylphosphocholine micelles and pore formation in planar lipid bilayers.

    abstract::The membrane-active, cationic, β-hairpin peptide, arenicin, isolated from marine polychaeta Arenicola marina exhibits a broad spectrum of antimicrobial activity. The peptide in aqueous solution adopts the significantly twisted β-hairpin conformation without pronounced amphipathicity. To assess the mechanism of arenici...


    pub_type: 杂志文章


    authors: Shenkarev ZO,Balandin SV,Trunov KI,Paramonov AS,Sukhanov SV,Barsukov LI,Arseniev AS,Ovchinnikova TV

    更新日期:2011-07-19 00:00:00

  • Protected sulfur transfer reactions by the Escherichia coli Suf system.

    abstract::The first step in sulfur mobilization for the biosynthesis of Fe-S clusters under oxidative stress and iron starvation in Escherichia coli involves a cysteine desulfurase SufS. Its catalytic reactivity is dependent on the presence of a sulfur acceptor protein, SufE, which acts as the preferred substrate for this enzym...


    pub_type: 杂志文章


    authors: Selbach BP,Pradhan PK,Dos Santos PC

    更新日期:2013-06-11 00:00:00

  • Transcription inhibition of oncogenic KRAS by a mutation-selective peptide nucleic acid conjugated to the PKKKRKV nuclear localization signal peptide.

    abstract::Mutations in the Kirsten ras (KRAS) gene are present in almost all pancreatic adenocarcinomas, and one common mutation is at codon 12: GGT (Gly) is transformed into GAT (Asp). In this work we have targeted the KRAS coding sequence embracing the GAT mutation with a sense PNA molecule (P14), with the aim of downregulati...


    pub_type: 杂志文章


    authors: Cogoi S,Codognotto A,Rapozzi V,Meeuwenoord N,van der Marel G,Xodo LE

    更新日期:2005-08-09 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

  • Identification and characterization of PshB, the dicluster ferredoxin that harbors the terminal electron acceptors F(A) and F(B) in Heliobacterium modesticaldum.

    abstract::The Type I homodimeric photosynthetic reaction center found in anaerobic gram-positive bacteria of the genus Heliobacteriaceae incorporates FA- and FB-like iron-sulfur clusters similar to those found in Photosystem I as terminal electron acceptors. We recently isolated the PshB protein that harbors the iron-sulfur clu...


    pub_type: 杂志文章


    authors: Heinnickel M,Shen G,Golbeck JH

    更新日期:2007-03-06 00:00:00

  • Multiple forms of phosphodeoxyribomutase from Escherichia coli. Physical and chemical characterization.

    abstract::Phosphodeoxyribomutase from Escherichia coli has been purified to homogeneity. Chromatography on DEAE-Sephadex revealed three peaks of enzyme activity, designated form I, form II, and form III. Form III could be further separated into form III-1 and form III-2 by polyacrylamide gel electrophoresis. The four different ...


    pub_type: 杂志文章


    authors: Leer JC,Hammer-Jespersen K

    更新日期:1975-02-11 00:00:00

  • Reaction mechanism of the iron-sulfur flavoenzyme adenosine-5'-phosphosulfate reductase based on the structural characterization of different enzymatic states.

    abstract::The iron-sulfur flavoenzyme adenosine-5'-phosphosulfate (APS) reductase catalyzes a key reaction of the global sulfur cycle by reversibly transforming APS to sulfite and AMP. The structures of the dissimilatory enzyme from Archaeoglobus fulgidus in the reduced state (FAD(red)) and in the sulfite adduct state (FAD-sulf...


    pub_type: 杂志文章


    authors: Schiffer A,Fritz G,Kroneck PM,Ermler U

    更新日期:2006-03-07 00:00:00

  • Reevaluation of the stoichiometry of cytochrome b559 in photosystem II and thylakoid membranes.

    abstract::The stoichiometry of cytochrome b559 (one or two copies) per reaction center of photosystem II (PSII) has been the subject of considerable debate. The molar ratio of cytochrome b559 has a number of significant implications on our understanding of the functional role of cytochrome b559, the mechanism of electron donati...


    pub_type: 杂志文章


    authors: Buser CA,Diner BA,Brudvig GW

    更新日期:1992-11-24 00:00:00