Abstract:
:Electron spin polarized electron paramagentic resonance (ESP EPR) spectra were obtained with deuterated iron-removed photosynthetic bacterial reaction centers (RCs) to specifically investigate the effect of the rate of primary charge separation, metal-site occupancy, and H-subunit content on the observed P865+QA- charge-separated state. Fe-removed and Zn-substituted RCs from Rb. sphaeroides R-26 were prepared by refined procedures, and specific electron transfer rates (kQ) from the intermediate acceptor H- to the primary acceptor QA of (200 ps)-1 vs (3-6 ns)-1 were observed. Correlation of the transient EPR and optical results shows that the observed slow kQ rate in Fe-removed RCs is H-subunit-independent, and, in some cases, independent of Fe-site occupancy as Zn2+ substitution does not ensure retention of the native kQ. In addition, shifts in the optical spectrum of P865 and differences in the high-field region of the Q-band ESP spectrum for Fe-removed RCs with slow kQ indicate possible structural changes near P865. The experimental X-band and Q-band spin-polarized EPR spectra for deuterated Fe-removed RCs where kQ is at least 15-fold slower at room temperature than the (200 ps)-1 rate observed for native Fe-containing RCs have different relative amplitudes and small g-value shifts compared to the spectra of Zn-RCs which have a kQ unchanged from native RCs. These differences reflect the trends in polarization predicted from the sequential electron transfer polarization (SETP) model [Morris et al. (1995) J. Phys. Chem. 99, 3854-3866; Tang et al. (1996) Chem. Phys. Lett. 253, 293-298]. Thus, SETP modeling of these highly resolved ESP spectra obtained with well-characterized proteins will provide definitive information about any light-induced structural changes of P865, H, and QA that occur upon formation of the P865+QA- charge-separated state.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Utschig LM,Greenfield SR,Tang J,Laible PD,Thurnauer MCdoi
10.1021/bi9630319subject
Has Abstractpub_date
1997-07-15 00:00:00pages
8548-58issue
28eissn
0006-2960issn
1520-4995pii
bi9630319journal_volume
36pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Subunit II of the aa3 type cytochrome c oxidase contains a binuclear copper center (CuA) which functions as the entry point for electrons donated by cytochrome c. We have introduced site-specific mutations in residues liganding the CuA center in the oxidase of the bacterium Paracoccus denitrificans; the purified, full...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962040e
更新日期:1997-03-18 00:00:00
abstract::The reactions of nitric oxide (NO) with the turnover intermediates of cytochrome c oxidase were investigated by combining amperometric and spectroscopic techniques. We show that the complex of nitrite with the oxidized enzyme (O) is obtained by reaction of both the "peroxy" (P) and "ferryl" (F) intermediates with stoi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000447k
更新日期:2000-12-19 00:00:00
abstract::Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors distantly related to phytochromes. Like phytochromes, CBCRs photointerconvert between two photostates that accompany photoisomerization of their bilin chromophores. While phytochromes typically exhibit red/far-red photocycles, CBCR photocycles are much mor...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi4015538
更新日期:2014-02-18 00:00:00
abstract::The one-for-one exchange of Cl(-) and HCO(3)(-) ions is catalyzed by human erythrocyte anion exchanger 1 (hAE1) through a ping-pong mechanism whereby the protein exists in two main conformations, with the single anion-binding site exposed at either the cytoplasmic (inner) side (E(i)) or the extracellular side (E(o)), ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051916r
更新日期:2006-05-23 00:00:00
abstract::Aspartoacylase catalyzes the deacetylation of N-acetylaspartic acid (NAA) to produce acetate and L-aspartate and is the only brain enzyme that has been shown to effectively metabolize NAA. Although the exact role of this enzymatic reaction has not yet been completely elucidated, the metabolism of NAA appears to be nec...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi052608w
更新日期:2006-05-09 00:00:00
abstract::The structure formed from the DNA oligonucleotide d(G4T4G4) (Oxy-1.5), which contains the Oxytricha telomere repeat T4G4, has been investigated by two-dimensional 1H and 31P NMR spectroscopy. Sequence-specific assignments have been obtained for the 1H and 31P resonances, using a combination of methods including compar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00084a040
更新日期:1993-08-24 00:00:00
abstract::In the cyanobacterium Anabaena, the precursor to tRNA(Leu) has a 249-nucleotide group I intron inserted between the wobble and second bases of the anticodon; the intron self-splices during transcription in vitro [Xu, M. Q., Kathe, S. D., Goodrich-Blair, H., Nierzwicki-Bauer, S. A., & Shub, D. A. (1990) Science 250, 15...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00082a016
更新日期:1993-08-10 00:00:00
abstract::Green sulfur bacteria possess two light-harvesting antenna systems, the chlorosome and the Fenna-Matthews-Olson (FMO) protein. In addition to self-aggregated bacteriochlorophyll (BChl) c, chlorosomes of Chlorobium tepidum contain a small amount of BChl a (ratio 100:1). The chlorosomal BChl a is associated with CsmA, a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi701616r
更新日期:2008-02-05 00:00:00
abstract::Insulin is very prone to form amyloid fibrils under slightly destabilizing conditions, and the B-chain region plays a critical role in the fibrillation. We show here that the isolated B-chain peptide of bovine insulin also forms fibrils at both acidic and neutral pH. When a mixture of insulin and the B-chain peptide w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051658y
更新日期:2005-12-20 00:00:00
abstract::Two oxygenated iron-cobalt hybrid hemoglobins (Hbs), (alpha Co-O2 beta Fe-O2)2 and (alpha Fe-O2 beta Co-O2)2, were studied by electron spin echo envelope modulation (ESEEM) spectroscopy in order to measure (i) electron-nuclear hyperfine and nuclear quadrupole coupling to the N epsilon of the proximal histidyl imidazol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00020a036
更新日期:1995-05-23 00:00:00
abstract::The plasma membrane serotonin transporter (SERT) has an important role in terminating serotonergic neurotransmission by re-uptake of 5-HT from the synaptic cleft. The expression of SERT on the cell surface is therefore a critical factor. In this study, we examined the role of the carboxyl terminus of SERT in trafficki...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0508688
更新日期:2006-01-31 00:00:00
abstract::Analogs of EPSP (4-8) have been prepared, and their activity as substrates for the chorismate synthase from Neurospora crassa has been characterized kinetically. The enzyme appears to show strict discrimination against substitution at the Z-position of the enol ether side chain as well as against substitution at the S...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00251a019
更新日期:1994-11-29 00:00:00
abstract::Although G protein-coupled receptor (GPCR) kinases (GRKs) have been shown to mediate desensitization of numerous GPCRs in studies using cellular expression systems, their function under physiological conditions is less well understood. In the current study, we employed various strategies to assess the effect of inhibi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi801056w
更新日期:2008-09-02 00:00:00
abstract::Aminoacylation of a transfer RNA (tRNA) by its cognate aminoacyl-tRNA synthetase relies upon the recognition of specific nucleotides as well as conformational features within the tRNA by the synthetase. In Escherichia coli, the aminoacylation of tRNA(His) by histidyl-tRNA synthetase (HisRS) is highly dependent upon th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035708f
更新日期:2004-02-03 00:00:00
abstract::Changes in the concentrations of high-energy phosphate metabolites were measured by 31P NMR spectroscopy of surviving rat uteri from 0-48 h following estrogen administration. Concentrations (millimoles per kilogram wet weight) of these metabolites in the untreated immature uterus, measured at 4 degrees C, were found t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00307a006
更新日期:1984-06-05 00:00:00
abstract::A manganese-dependent 3,4-dihydroxyphenylactate 2,3-dioxygenase from Arthrobacter globiformis strain CM-2 (MndD) cloned in Escherichia coli has been purified to homogeneity. Sedimentation equilibrium analysis indicates an alpha 4 homotetrameric holoenzyme structure (4 x 38,861 Da). Steady-state kinetic analysis of Mnd...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi951979h
更新日期:1996-01-09 00:00:00
abstract::The interaction of the 2'-phosphate-containing nucleotides (NADP+, NADPH, 2'-phosphoadenosine 5'-diphosphoribose, and adenosine 2',5'-bisphosphate) with NADP+ -specific isocitrate dehydrogenase was studied by using 31P NMR spectroscopy. The separate resonances corresponding to free and bound nucleotides, characteristi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00303a015
更新日期:1984-04-10 00:00:00
abstract::Heme-derived linear tetrapyrroles (phytobilins) in phycobiliproteins and phytochromes perform critical light-harvesting and light-sensing roles in oxygenic photosynthetic organisms. A key enzyme in their biogenesis, phycocyanobilin:ferredoxin oxidoreductase (PcyA), catalyzes the overall four-electron reduction of bili...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi100728q
更新日期:2010-07-27 00:00:00
abstract::The primary photochemical event of photoactive yellow protein (PYP) was studied by laser flash photolysis experiments on a subpicosecond-nanosecond time scale. PYP was excited by a 390-nm pulse, and the transient difference absorption spectra were recorded by a multichannel spectrometer for a more reliable spectral an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002437p
更新日期:2001-05-22 00:00:00
abstract::The pK(a) values measured previously for the internal Lys-66, Asp-66, and Glu-66 in variants of a highly stable form of staphylococcal nuclease are shifted by as many as 5 pK(a) units relative to normal pK(a) values in water. These shifts cannot be reproduced with continuum electrostatics calculations with static stru...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi902114m
更新日期:2010-05-18 00:00:00
abstract::Mixtures of 1,2-dipalmitoylglycerol (1,2-DPG), 1,2-dioleylglycerol (1,2-DOG), 1,2-dicapryloylglycerol (1,2-DCG), 1,3-dioleylglycerol (1,3-DOG), and 1,3-dicapryloylglycerol (1,3-DCG) with dipalmitoylphosphatidylcholine (DPPC) have been studied by means of differential scanning calorimetry (DSC) and fluorescence depolar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00425a022
更新日期:1988-12-13 00:00:00
abstract::The light chain of activated factor IX (FIXa) is involved in a number of functional properties, including FIXa enzymatic activity. This suggests the existence of a functional link between the FIXa light chain and the catalytic domain. The FIXa structure includes a few putative interactions between EGF2 and the proteas...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi060451h
更新日期:2006-09-05 00:00:00
abstract::The cation complexation equilibria between ionophore A23187 and several alkaline earth and first transition series divalent cations have been investigated. Absorption and fluorescence spectroscopy were used to monitor the reactions which were studied in solutions of 80% methanol/water, at 25 degrees C, and under condi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00390a019
更新日期:1987-08-11 00:00:00
abstract::The effects of Ca2+, Mg2+, and troponin I (TnI) inhibitory peptide (Ip) binding on the spectral properties of a Phe-154 to Trp mutant (F154W) of chicken recombinant troponin C (rTnC) have been examined. Residue 154 is positioned in the final flanking helix H of metal binding site IV. Since there are no other Tyr or Tr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00176a028
更新日期:1994-03-15 00:00:00
abstract::The nitrogenase MoFe protein contains the active site metallocluster called FeMo-cofactor [7Fe-9S-Mo-homocitrate] that exhibits an S = 3/2 EPR signal in the resting state. No interaction with FeMo-cofactor is detected when either substrates or inhibitors are incubated with MoFe protein in the resting state. Rather, th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011571m
更新日期:2001-11-20 00:00:00
abstract::Studies of the mechanism of protein secretion in a Gram-positive bacterium, Bacillus subtilis, yielded results very similar to those previously obtained with a Gram-negative organism: nascent chains protruding from protoplasts could be labeled extracellularly; the labeled chains could be recovered on polysomes isolate...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00568a030
更新日期:1979-01-09 00:00:00
abstract::The in vitro hydrolysis by porcine kidney prolidase of the imidodipeptide L-alanyl-L-proline was monitored by using 1H high-resolution NMR spectroscopy. The dipeptide exists as an equilibrium mixture of isomers with cis or trans conformation about the peptide bond. The 13C and 1H NMR spectra of the dipeptide displayed...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00353a016
更新日期:1986-03-11 00:00:00
abstract::A ribonuclease that hydrolyzes either linear duplex or single-stranded RNA in an exonucleolytic manner has been partially purified from Ehrlich ascites tumor cell nucleoli and is free from other ribonucleases. The enzyme will also degrade the RNA complement of an RNA X DNA duplex; however, no nuclease activity is obse...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00324a022
更新日期:1985-01-29 00:00:00
abstract::Iron is vital for almost all organisms because of its ability to donate and accept electrons with relative ease. It serves as a cofactor for many proteins and enzymes necessary for oxygen and energy metabolism, as well as for several other essential processes. Mammalian cells utilize multiple mechanisms to acquire iro...
journal_title:Biochemistry
pub_type: 杂志文章,评审
doi:10.1021/bi300752r
更新日期:2012-07-24 00:00:00
abstract::To study whether protein kinase C (PKC) isoforms can interact with protein-tyrosine-phosphatases (PTPs) which are connected to the insulin signaling pathway, we co-overexpressed PKC isoforms together with insulin receptor, docking proteins, and the PTPs SHP1 and SHP2 in human embryonic kidney (HEK) 293 cells. After ph...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011327v
更新日期:2002-01-15 00:00:00