Abstract:
:Electron-transfer reactions following the formation of P700(+)A1- have been studied in isolated Photosystem I complexes from Synechococcus elongatus between 300 and 5 K by flash absorption spectroscopy. (1) In the range from 300 to 200 K, A1- is reoxidized by electron transfer to the iron-sulfur cluster FX. The rate slows down with decreasing temperature, corresponding to an activation energy of 220 +/- 20 meV in this temperature range. Analyzing the temperature dependence of the rate in terms of nonadiabatic electron-transfer theory, one obtains a reorganization energy of about 1 eV and an edge-to-edge distance between A1 and FX of about 8 A assuming the same distance dependence of the electron-transfer rate as in purple bacterial reaction centers. (2) At temperatures below 150 K, different fractions of PS I complexes attributed to frozen conformational substates can be distinguished. A detailed analysis at 77 K gave the following results: (a) In about 45%, flash-induced electron transfer is limited to the formation and decay of the secondary pair P700(+)A1-. The charge recombination occurs with a t1/2 of about 170 micros. (b) In about 20%, the state P700(+)FX- is formed and recombines with complex kinetics (t1/2 = 5-100 ms). (c) In about 35%, irreversible formation of P700(+)FA- or P700(+)FB- is possible. (3) The transition from efficient forward electron transfer at higher temperatures to heterogeneous photochemistry at low temperatures has been investigated in different glass-forming solvents. The yield of forward electron transfer to the iron-sulfur clusters decreases in a narrow temperature interval. The temperature of the half-maximal effect varies between different solvents and appears to be correlated with their liquid to glass transition. It is proposed that reorganization processes in the surroundings of the reactants which are required for the stabilization of the charge-separated state become arrested near the glass transition. This freezing of protein motions and/or solvent reorganization may affect electron-transfer reactions through changes in the free-energy gap and the reorganization energy. (4) The rate of charge recombination between P700(+) and A1- increases slightly (about 1.5-fold) when the temperature is decreased from 300 to 5 K. This charge recombination characterized by a large driving force is much less influenced by the solvent properties than the forward electron-transfer steps from A1- to FX and FA/B.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Schlodder E,Falkenberg K,Gergeleit M,Brettel Kdoi
10.1021/bi973182rsubject
Has Abstractpub_date
1998-06-30 00:00:00pages
9466-76issue
26eissn
0006-2960issn
1520-4995pii
bi973182rjournal_volume
37pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::MerR, the metalloregulator of the mercury resistance (mer) operon, binds the operator (merO)between -10 and -35 of the merTPCAD promoter (PT) and sequesters RNA polymerase (RNAP) in a closed complex. MerR represses PT until Hg(II) induces it to underwind merO DNA and thus facilitate open complex formation. We used cro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982814m
更新日期:1999-03-16 00:00:00
abstract::The Mn4 complex which is involved in water oxidation in photosystem II (PSII) is known to exhibit two types of EPR signals in the S2 state, one of the five redox states of the enzyme cycle: either a multiline signal (S = 1/2) or a signal at g = 4.1 (S = 3/2 or S= 5/2). The S = 1/2 state can be converted to that respon...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9728710
更新日期:1998-03-24 00:00:00
abstract::Transcarboxylase (TC) is a multisubunit enzyme that catalyzes the transfer of a carboxylate group from methylmalonyl-CoA (MMCoA) to pyruvate. The CO2- group is shuttled between the MMCoA and pyruvate binding sites by a biotin cofactor, covalently linked to the 1.3S subunit. Fully carboxylated 1.3S can be prepared in v...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0116442
更新日期:2002-02-19 00:00:00
abstract::PKC phosphorylation regulates PITX2 DNA binding and transcriptional activity. Mutation of individual PKC sites demonstrates the functional regulation of PITX2 through phosphorylation. Immunoprecipitation of PITX2 and a PITX2 PKC mutant protein reveal specific in vivo phosphorylation by PKC in transfected cells. The tr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048362x
更新日期:2005-03-15 00:00:00
abstract::The bond cleavage step of pepsinogen activation has been investigated in a kinetic study in which the denatured products of short-term acidifications were separated on SDS-polyacrylamide gels and the peptide products were quantitated by densitometry. Although several peptide products were observed, under the condition...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00432a040
更新日期:1989-03-21 00:00:00
abstract::Nitrobenzamido ligands linked to the DNA intercalator 9-aminoacridine via poly(methylene) chains induce single-strand nicks in DNA upon irradiation with long-wavelength ultraviolet light (lambda greater than or equal to 300 nm). Optimal photocleavage activity was found for the reagent 9-[[6-(4-nitrobenzamido)hexyl]ami...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00417a021
更新日期:1988-08-23 00:00:00
abstract::Self-splicing of Tetrahymena pre-rRNA proceeds in two consecutive phosphoryl transesterification steps. One major difference between these steps is that in the first an exogenous guanosine (G) binds to the active site, while in the second the 3'-terminal G414 residue of the intron binds. The first step has been extens...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9527653
更新日期:1996-05-07 00:00:00
abstract::The combination of UV/visible/near-IR variable-temperature magnetic circular dichroism (VTMCD) and EPR spectroscopies has been used to investigate the spin states and axial ligation of the heme group in oxidized, reduced, and CO-bound reduced forms of the Rhodospirillum rubrum CO oxidation transcriptional activator pr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi991303c
更新日期:1999-09-28 00:00:00
abstract::The three-dimensional structure of toxic shock syndrome toxin 1 (TSST-1) from Staphylococcus aureus has been determined and refined to an R value of 0.226 for data between 8- and 2.5-A resolution. Overall, the structure of TSST-1 is similar to that of another superantigen, staphylococcal enterotoxin B (SEB). The key d...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00213a001
更新日期:1993-12-21 00:00:00
abstract::Indolicidin is an antimicrobial cationic peptide with broad-spectrum activity isolated from bovine neutrophils. An indolicidin analogue CP-11, ILKKWPWWPWRRK-NH(2), with improved activity against Gram-negative bacteria had increased positive charge and amphipathicity while maintaining the short length of the parent mol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035643g
更新日期:2003-12-09 00:00:00
abstract::The reaction of nitric oxide (NO) with fast cytochrome bo from Escherichia coli has been studied by electronic absorption, MCD, and EPR spectroscopy. Titration of the enzyme with NO showed the formation of two distinct species, consistent with NO binding stoichiometries of 1:1 and 2:1 with observed dissociation consta...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi971481a
更新日期:1997-12-23 00:00:00
abstract::Bovine brain adenylate cyclase was solubilized with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), sodium cholate, sodium deoxycholate, or these detergents plus (NH4)2SO4. The specific activity of the extract obtained with 13 mM CHAPS alone was several times those of the other detergent extracts wi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00258a019
更新日期:1982-07-20 00:00:00
abstract::The nuclear tRNA 3' processing activity from wheat has been characterized and partially purified. Several characteristics of the wheat nuclear 3' processing enzyme now allow this activity to be distinguished from its mitochondrial counterpart. The nuclear enzyme is an endonuclease, which we termed nuclear RNase Z. The...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi992253e
更新日期:2000-02-29 00:00:00
abstract::Adenylosuccinate synthetase catalyzes the first committed step in the de novo biosynthesis of AMP, coupling L-aspartate and IMP to form adenylosuccinate. Km values of IMP and 2'-deoxy-IMP are nearly identical with each substrate supporting comparable maximal velocities. Nonetheless, the Km value for L-aspartate and th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0607498
更新日期:2006-09-26 00:00:00
abstract::His51 in horse liver alcohol dehydrogenase (ADHE) has been proposed to act as a proton donor/acceptor in the NAD+/NADH-dependent oxidation/reduction of alcohol/aldehyde. The residue corresponding to His51 of ADHE is Val51 (Val45 in the protein sequence) in benzyl alcohol dehydrogenase (BADH) encoded by TOL plasmid pWW...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970726g
更新日期:1998-03-10 00:00:00
abstract::We have used diethyl pyrocarbonate (DEP), which carbethoxylates adenine bases, and dimethyl sulfate (DMS), which methylates guanine residues and single-stranded cytosines, to probe bases in open complexes between RNA polymerase and the lac UV5 promoter in vitro. We compared the kinetics of reactivity between bases in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00436a040
更新日期:1989-05-16 00:00:00
abstract::As part of a high-throughput, structural proteomic project we have used NMR spectroscopy to determine the solution structure and ascertain the function of a previously unknown, conserved protein (MtH895) from the thermophilic archeon Methanobacterium thermoautotrophicum. Our findings indicate that MtH895 contains a ce...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0115176
更新日期:2002-04-16 00:00:00
abstract::The energy derived from optimized van der Waals interactions in closely packed, folded proteins has been proposed to be of similar energetic magnitude to hydrophobicity in stabilizing the native state. If packing is this energetically important, it should influence the evolution of protein core sequences. To test this...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011776v
更新日期:2001-12-18 00:00:00
abstract::Oxidation of low-density lipoprotein (LDL), the major cholesterol carrier in plasma, is thought to promote atherogenesis via several mechanisms. One proposed mechanism involves fusion of oxidized LDL in the arterial wall; another involves oxidation-induced amyloid formation by LDL apolipoprotein B. To test these mecha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700225a
更新日期:2007-05-15 00:00:00
abstract::Volumetric characteristics of protein recognition events determine the direction of pressure-induced shifts in the recognition reaction, while also providing insights into the structural, dynamic, and hydration changes. We report changes in volume, ΔV, and adiabatic compressibility, ΔK(S), accompanying the binding of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi3006994
更新日期:2012-07-24 00:00:00
abstract::Liver alcohol dehydrogenase (LADH) carboxymethylated at Cys-46 (CMLADH) forms two different ternary complexes with 4-trans-(N,N-dimethylamino)cinnamaldehyde (DACA). The complex with reduced nicotinamide adenine dinucleotide (NADH) is characterized by a 38-nm red shift of the long-wavelength pi, pi* transition to 436 n...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00321a085
更新日期:1984-12-18 00:00:00
abstract::β-Lactam antibiotics have faced obsolescence with the emergence of methicillin-resistant Staphylococcus aureus (MRSA). A complex set of events ensues upon exposure of MRSA to these antibiotics, which culminates in proteolysis of BlaI or MecI, two gene repressors, and results in the induction of resistance. We report s...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500074w
更新日期:2014-03-18 00:00:00
abstract::The enthalpies of transfer of hen egg white lysozyme from water to aqueous solutions of 1-propanol were determined by isothermal flow calorimetry at 10, 17, 25, and 40 degrees C in 0.04 M, pH 2 glycine buffer. Alcohol concentrations up to 3.4 M were employed. Four regions in the dependence of the enthalpy of transfer ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00514a016
更新日期:1981-05-26 00:00:00
abstract::Cyanobacteriochromes (CBCRs) are photosensory proteins related to the red/far-red phytochromes. Like phytochromes, CBCRs use linear tetrapyrrole (bilin) chromophores covalently attached via a thioether linkage to a conserved Cys residue also found in plant and cyanobacterial phytochromes. Unlike almost all phytochrome...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300171s
更新日期:2012-05-01 00:00:00
abstract::Cytidine deaminase from Escherichia coli contains 1 mol of tightly bound zinc per enzyme subunit (Yang, C., Carlow, D., Wolfenden, R., & Short, S.A. (1992) Biochemistry 31, 4168-4174). When the metal liganding residues Cys-129 and Cys-132 were replaced by Ala, and His-102 was replaced by Ala, Asn, or Gln, deaminase ac...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00187a012
更新日期:1994-05-31 00:00:00
abstract::A core Y61F mutant of the gene 5 single-stranded DNA-binding protein (g5p) of f1 bacterial virus aggregated when expressed from a plasmid, but, after refolding in vitro, it behaved much like wild-type and may be a stability or folding mutant. Circular dichroism (CD) titrations showed the same cooperative polynucleotid...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi972545k
更新日期:1998-05-19 00:00:00
abstract::Spectroscopic methods are used to probe the interactions of several anilinoacridine analogues with calf thymus DNA over a wide range of temperatures and sodium chloride concentrations. The structurally similar compounds m-AMSA, AMSA (both active as antitumor agents), and o-AMSA (inactive as an antitumor agent) have be...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00231a025
更新日期:1991-04-30 00:00:00
abstract::Mitochondria isolated from coenzyme Q deficient yeast cells had no detectable NADH:cytochrome c reductase or succinate:cytochrome c reductase but had comparable amounts of cytochromes b and c1 as wild-type mitochondria. Addition of succinate to the mutant mitochondria resulted in a slight reduction of cytochrome b; ho...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00372a029
更新日期:1986-12-02 00:00:00
abstract::The toll that Streptococcus pneumoniae exacts on the welfare of humanity is enormous. This organism claims the lives of approximately 3700 people daily, the majority of whom are children below the age of 5, and the situation could worsen due to the increasing incidence of pernicious, multiple-antibiotic-resistant stra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048075t
更新日期:2004-12-28 00:00:00
abstract::The high resolution proton nuclear magnetic resonance (NMR) spectra of the synthetic DNA block polymer d(C15A15)-d(T15G15) were studied in order to more completely understand telestability in DNA, and to provide fundamental NMR data on DNA helices and random coils. Spectra were measured in the spectral region from 0 t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00622a031
更新日期:1977-02-08 00:00:00