Abstract:
:The X-ray crystallographic structure of the photosynthetic reaction center from Rhodobacter sphaeroides obtained at high resolution has revealed a number of internal water molecules (Ermler, U., Fritzsch, G., Buchanan, S. K., and Michel, H. (1994) Structure 2, 925-936; Stowell, M. H. B., McPhillips, T. M., Rees, D. C., Soltis, S. M., Abresch, E., and Feher, G. (1997) Science 276, 812-816). Some of them are organized into distinct hydrogen-bonded water chains that connect Q(B) (the terminal quinone electron acceptor of the reaction center) to the aqueous phase. To investigate the role of the water chains in the proton conduction process, proline L209, located immediately adjacent to a water chain, was mutated to the following residues: F, Y, W, E, and T. We have first analyzed the effects of the mutations on the kinetic and thermodynamic properties of the rate constants of the second electron transfer (k(AB)(2)) and of the coupled proton uptake (k(H)+) at the second flash. In all aromatic mutants, k(AB)(2) and k(H)+ are notably and concomitantly decreased compared to the wild-type, while no effect is observed in the other mutants. The temperature dependence of these rates shows activation energy values (DeltaH) similar for the proton and electron-transfer processes in the wild-type and in most of the mutants, except for the L209PW and L209PF mutants. The analysis of the enthalpy factors related to the electron and proton-transfer processes in the L209PF and the L209PW mutants allows to distinguish the respective effects of the mutations for both transfer reactions. It is noteworthy that in the aromatic mutants a substantial increase of the free energies of activation is observed (DeltaG(L209PY) < DeltaG(L209PF) < DeltaG(L209PW)) for both proton and electron-transfer reactions, while in the other mutants, DeltaG is not affected. The salt concentration dependence of k(AB)(2) shows, in the L209PF and L209PW mutants, a higher screening of the protein surface potential experienced by Q(B). Our data suggest that residues F and W in position L209 increase the polarizability of the internal water molecules and polar residues by altering the organization of the hydrogen-bond network. We have also analyzed the rates of the first electron-transfer reaction (k(AB)(1)), in the 100 micros time domain. These kinetics have previously been shown to reflect protein relaxation events possibly including proton uptake events (Tiede, D. M., Vazquez, J., Cordova, J., and Marone, P. M. (1996) Biochemistry 35, 10763-10775). Interestingly, in the L209PF and L209PW mutants, k(AB)(1) is notably decreased in comparison to the wild type and the other mutants, in a similar way as k(AB)(2) and k(H)+. Our data imply that the dynamic organization of this web is tightly coupled to the electron transfer process that is kinetically limited by protonation events and/or conformational rearrangements within the protein.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Tandori J,Sebban P,Michel H,Baciou Ldoi
10.1021/bi990192esubject
Has Abstractpub_date
1999-10-05 00:00:00pages
13179-87issue
40eissn
0006-2960issn
1520-4995pii
bi990192ejournal_volume
38pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Pig pancreatic alpha-amylase (PPA), an enzyme belonging to the alpha-amylase family, is involved in the degradation of starch. Like some other members of this family, PPA requires chloride to reach maximum activity levels. To further explain the mechanism of chloride activation, a crystal of wild-type PPA soaked with ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048201t
更新日期:2005-03-08 00:00:00
abstract::ZntA from Escherichia coli confers resistance to toxic concentrations of Pb2+, Zn2+, and Cd2+. It is a member of the P1B-ATPase transporter superfamily, which includes the human Cu+-transporting proteins ATP7A and ATP7B. P1B-type ATPases typically have a hydrophilic N-terminal metal-binding domain and eight transmembr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.0c00770
更新日期:2020-12-01 00:00:00
abstract::Plasminogen activator inhibitor-1 (PAI-1) is a serine protease inhibitor of the serpin superfamily which rapidly inactivates tissue plasminogen activator (tPA), but reacts with thrombin at a much slower rate. Based on the previous mutagenesis studies and the X-ray crystal structure of the thrombin E192Q-bovine pancrea...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9808518
更新日期:1998-09-22 00:00:00
abstract::The fibrillation of misfolded neurodegenerative disease-related proteins has been extensively studied over the past few decades, but the initial oligomerization has been rarely examined even though some recent evidence indicated that small protein oligomers are more neurotoxic than long protein fibers. It is rather di...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b00966
更新日期:2017-12-19 00:00:00
abstract::Human type beta 2 transforming growth factor (hTGF-beta 2) was purified from tamoxifen-supplemented, serum-free medium conditioned by the human prostatic adenocarcinoma cell line PC-3. The purification of hTGF-beta 2 was monitored in a growth inhibition assay and was achieved by batch purification on methylsilyl-contr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00383a002
更新日期:1987-05-05 00:00:00
abstract::The stoichiometry of the nitrogenase ATP-dependent H2 evolution and ecetylene reduction reactions using S2O4(2-) as an electron source was studied by various techniques. For each mole of S2O4(2-) oxidized to 2SO3(2-) by the enzyme-catalyzed reactions at 25 degrees and pH 8, 1 mol of H2 (1 mol of ethylene for acetylene...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00690a019
更新日期:1975-09-23 00:00:00
abstract::Organophosphate flame retardants are used to inhibit combustion and increase plasticity in plastics and durable foams. While not neurotoxic, these compounds are potential carcinogens, endocrine disrupters, and developmental toxins. The phosphotriesterase from Sphingobium sp. TCM1 (Sb-PTE) is unique among phosphotriest...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.0c00089
更新日期:2020-03-31 00:00:00
abstract::Oligonucleotides capable of sequence-specific triple helix formation have been proposed as DNA binding ligands useful for modulation of gene expression and for directed genome modification. However, the effectiveness of such triplex-forming oligonucleotides (TFOs) depends on their ability to bind to their target sites...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982290q
更新日期:1999-02-09 00:00:00
abstract::Protease inhibition by metastable serine protease inhibitors (serpins) is mediated by one of the largest functional intradomain conformational changes known in biology. In this extensive structural rearrangement, protease-serpin complex formation triggers cleavage of the serpin reactive center loop (RCL), its subseque...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.6b00839
更新日期:2017-01-31 00:00:00
abstract::Apolipophorin III (apoLp-III) from the greater wax moth Galleria mellonella is an exchangeable insect apolipoprotein that consists of five amphipathic alpha-helices, sharing high sequence identity with apoLp-III from the sphinx moth Manduca sexta whose structure is available. To define the minimal requirement for apoL...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0013804
更新日期:2001-03-13 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::One of the distinctive features of eubacterial retinal-based proton pumps, proteorhodopsins, xanthorhodopsin, and others, is hydrogen bonding of the key aspartate residue, the counterion to the retinal Schiff base, to a histidine. We describe properties of the recently found eubacterium proton pump from Exiguobacteriu...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300409m
更新日期:2012-07-24 00:00:00
abstract::Vitamin D receptor (VDR) is a member of the nuclear hormone receptor superfamily. When bound to a variety of vitamin D analogues, VDR manifests a wide diversity of physiological actions. The molecular mechanism by which different vitamin D analogues cause specific responses is not understood. The published crystallogr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi201637p
更新日期:2011-12-27 00:00:00
abstract::Ferrochelatase is the terminal enzyme in the heme biosynthetic pathway. It catalyzes the insertion of ferrous iron into protoporphyrin IX to produce protoheme IX. The crystal structures of ferrochelatase from Saccharomyces cerevisiae in free form, in complex with Co(II), a substrate metal ion, and in complex with two ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0260785
更新日期:2002-11-19 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::The sterol (free and esterified cholesterol) transport activity of the small-intestinal brush border membrane was solubilized with the short-chain detergent diheptanoylphosphatidylcholine and reconstituted to an artificial membrane system (proteoliposomes). The resulting proteoliposomes were identified as unilamellar ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970625i
更新日期:1997-09-02 00:00:00
abstract::To understand the relationship between the chemical structure of polar molecules and their membrane location, the behavior of dansyl (dimethylaminonaphthalenesulfonyl) and related polar fluorescent probes was examined. The depth of these probes in lipid bilayers was determined by parallax analysis of fluorescence quen...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9726234
更新日期:1998-03-31 00:00:00
abstract::We describe the crystal structure of human epidermal-type fatty acid binding protein (E-FABP) that was recently found to be highly upregulated in human psoriatic keratinocytes. To characterize E-FABP with respect to ligand-binding properties and tertiary structure, we cloned the respective cDNA, overexpressed the prot...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990305u
更新日期:1999-09-21 00:00:00
abstract::In the course of measuring the concentrations of retinoic acids (RA) in bovine plasma, a major peak was observed which comigrated with 9-cis-RA on normal-phase high-performance liquid chromatography. Rechromatography of this retinoic on reverse-phase high-performance liquid chromatography showed that it was distinct f...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00004a013
更新日期:1995-01-31 00:00:00
abstract::Iron K-edge X-ray spectroscopy (XANES and EXAFS) was used to study iron coordination in frozen solutions of soybean lipoxygenase-1 (SLO). The intensity of the 1s-->3d pre-edge transition of native iron(II) lipoxygenase is greater than what was found for six-coordinate high-spin iron(II) model complexes, but comparable...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00254a011
更新日期:1994-12-20 00:00:00
abstract::Sterol carrier protein 2 like 2 from Aedes aegypti (AeSCP2L2) plays an important role in lipid transport in mosquitoes for its routine metabolic processes. Repeated unsuccessful attempts to crystallize ligand free SCP2L2 prompted us to undertake nuclear magnetic resonance (NMR) spectroscopy to determine its three-dime...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.6b00322
更新日期:2016-09-06 00:00:00
abstract::De novo purine biosynthesis proceeds by two divergent paths. In bacteria, yeasts, and plants, 5-aminoimidazole ribonucleotide (AIR) is converted to 4-carboxy-AIR (CAIR) by two enzymes: N(5)-carboxy-AIR (N(5)-CAIR) synthetase (PurK) and N(5)-CAIR mutase (class I PurE). In animals, the conversion of AIR to CAIR requires...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi102033a
更新日期:2011-05-31 00:00:00
abstract::The role of the 2'-hydroxyl group in RNA--protein interaction has been investigated using MS2 coat protein and its hairpin RNA operator as a model system. Derivatives of the MS2 translational operator were prepared where individual riboses were replaced by deoxyribose and their binding affinities to MS2 coat protein w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00038a033
更新日期:1995-09-26 00:00:00
abstract::Binding of mitochondrial cyclophilin (CyP) to the inner mitochondrial membrane is induced by treatment of mitochondria with thiol reagents or oxidative stress and correlates with a sensitization to [Ca2+] of the cyclosporin A-sensitive mitochondrial permeability transition pore (MTP) [Connern, C. P., & Halestrap, A. P...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9525177
更新日期:1996-06-25 00:00:00
abstract::Mdm2 negatively regulates p53 by inhibiting its transcriptional activity and promoting its degradation by functioning as an E3 ubiquitin ligase. The primary p53 binding site on mdm2 is located in its N-terminal domain. Through binding to p53 at its N-terminal transactivation domain, mdm2 directly blocks the transcript...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi060661u
更新日期:2006-08-01 00:00:00
abstract::A rapid assay procedure was developed for cleavage of the N-terminal propeptides of procollagen. With the assay a neutral procollagen N-protease was purified about 300-fold from chick embryo tendon extract. The enzyme had an apparent molecular weight of 260 000 and a pH optimum of 7.4. Ca2+ was required for enzymic ac...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00608a002
更新日期:1978-07-25 00:00:00
abstract::Calmodulin (CaM) is an essential, eukaryotic protein comprised of two highly homologous domains (N and C). CaM binds four calcium ions cooperatively, regulating a wide array of target proteins. A genetic screen of Paramecia by Kung [Kung, C. et al. (1992) Cell Calcium 13, 413-425] demonstrated that the domains of CaM ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061134d
更新日期:2006-12-05 00:00:00
abstract::Transient contacts between denatured polypeptide chains are likely to play an important part in the initial stages of protein aggregation and fibrillation. To analyze the nature of such contacts, we have carried out a protein engineering study of the 102-residue protein U1A, which aggregates transiently in the wild-ty...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048509k
更新日期:2004-10-19 00:00:00
abstract::The heme-regulated inhibitor (HRI) of protein synthesis becomes activated in rabbit reticulocyte lysates in response to a variety of conditions including heme-deficiency, addition of oxidants, and heat shock. Activated HRI inhibits translation by catalyzing the phosphorylation of the alpha-subunit of eukaryotic initia...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00080a001
更新日期:1993-07-27 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