Abstract:
:P700, the primary electron donor of photosystem I is an asymmetric dimer made of one molecule of chlorophyll a' (P(A)) and one of chlorophyll a (P(B)). While the carbonyl groups of P(A) are involved in hydrogen-bonding interactions with several surrounding amino acid side chains and a water molecule, P(B) does not engage in hydrogen bonding with the protein. Light-induced FTIR difference spectroscopy of the photooxidation of P700 has been combined with site-directed mutagenesis in Synechocystis sp. PCC 6803 to investigate the influence of these hydrogen bonds on the structure of P700 and P700(+). When the residue Thr A739, which donates a hydrogen bond to the 9-keto C=O group of P(A), is changed to Phe, a differential signal at 1653(+)/1638(-) cm(-1) in the P700(+)/P700 FTIR difference spectrum upshifts by approximately 30-40 cm(-1), as expected for the rupture of the hydrogen bond or, at least, a strong decrease of its strength. The same upshift is also observed in the FTIR spectrum of a triple mutant in which the residues involved in the three main hydrogen bonds to the 9-keto and 10a-carbomethoxy groups of P(A) have been changed to the symmetry-related side chains present around P(B). In addition, the spectrum of the triple mutant shows a decrease of a differential signal around 1735 cm(-1) and the appearance of a new signal around 1760 cm(-1). This is consistent with the perturbation of a bound 10a-ester C=O group that becomes free in the triple mutant. All of these observations support the assignment scheme proposed previously for the carbonyls of P700 and P700(+) [Breton, J., Nabedryk, E., and Leibl, W. (1999) Biochemistry 38, 11585-11592] and therefore reinforce our previous conclusions that the positive charge in P700(+) is largely delocalized over P(A) and P(B).
journal_name
Biochemistryjournal_title
Biochemistryauthors
Pantelidou M,Chitnis PR,Breton Jdoi
10.1021/bi049515jsubject
Has Abstractpub_date
2004-07-06 00:00:00pages
8380-90issue
26eissn
0006-2960issn
1520-4995journal_volume
43pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Photochemical studies of the effects of temperature, pH, and dehydration on the formation and back photoreaction of the M412 intermediate in the photocycle of light-adapted bacteriorhodopsin (bR570) are carried out. Continuous illumination experiments in the range between -40 and -90 degrees C indicate that at low tem...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00506a031
更新日期:1981-02-03 00:00:00
abstract::We have developed a new genomic sequencing method for detecting, with resolution at the nucleotide level, the interstrand DNA cross-links induced by 4,5',8-trimethylpsoralen along single-copy genes in mammalian cells. The cross-links (diadducts) initially formed are converted into monoadducts by alkali reversal prior ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002539f
更新日期:2001-04-03 00:00:00
abstract::The kinetics of folding/unfolding of cross-linked Lys7-dinitrophenylene-Lys41-ribonuclease A were studied and compared to those of unmodified ribonuclease A (RNase A) at various concentrations of guanidine hydrochloride. The folding of the denatured cross-linked protein involved one fast-folding species (22 +/- 4%) an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00332a013
更新日期:1985-05-21 00:00:00
abstract::Cysteine dioxygenase (CDO) is a non-heme monoiron enzyme with an unusual posttranslational modification in the proximity of the ferrous iron active site. This modification, a cysteine to tyrosine thioether bond, cross-links two β-strands of the β-barrel. We have investigated its role in catalysis through a combined cr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi501277a
更新日期:2014-12-23 00:00:00
abstract::Chicken histone H4, labeled separately at Met-84 with N-[[(iodoacetyl)amino]ethyl]-5-naphthylamine-1-sulfonic acid and 5-(iodoacetamido)fluorescein, was reassociated with unlabeled histones H2A, H2B, and H3 and 146 base pairs of DNA to produce fluorescently labeled nucleosomes having physical characteristics virtually...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00366a010
更新日期:1986-09-09 00:00:00
abstract::Nitric oxide generated by bacterial nitric oxide synthase (NOS) increases the susceptibility of Gram-positive pathogens Staphylococcus aureus and Bacillus anthracis to oxidative stress, including antibiotic-induced oxidative stress. Not surprisingly, NOS inhibitors also improve the effectiveness of antimicrobials. Dev...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00431
更新日期:2015-07-07 00:00:00
abstract::Studies reveal that it is possible to design a palladium(II)-containing porphyrin to bind exclusively by intercalation to double-stranded DNA while simultaneously enhancing the ability to sensitize the formation of singlet oxygen. The comparisons revolve around the cations [5,10,15,20-tetra(N-methylpyridinium-4-yl)por...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi401610t
更新日期:2014-02-04 00:00:00
abstract::The hammerhead ribozyme undergoes a well-defined two-stage conformational folding process, induced by the binding of magnesium ions. In this study, we have used isothermal titration calorimetry to analyze the thermodynamics of magnesium binding and magnesium ion-induced folding of the ribozyme. Binding to the natural ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002231o
更新日期:2001-02-06 00:00:00
abstract::Glycogen phosphorylase is a muscle enzyme which metabolizes glycogen, producing glucose-1-phosphate, which can be used for the production of ATP. Phosphorylase activity is regulated by phosphorylation/dephosphorylation, and by the allosteric binding of numerous effectors. In this work, we have studied 10 site-directed...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0020372
更新日期:2001-05-01 00:00:00
abstract::CYP2C19 is selective for the 4'-hydroxylation of S-mephenytoin while the highly similar CYP2C9 has little activity toward this substrate. To identify critical amino acids determining the specificity of human CYP2C19 for S-mephenytoin 4'-hydroxylation, we constructed chimeras by replacing portions of CYP2C9 containing ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi001678u
更新日期:2001-02-20 00:00:00
abstract::Data are presented which suggest that photosystem II dependent hydrogen ion accumulation and ATP synthesis can occur only after the lamellar membranes have undergone a conformational change. This membrane conformational change is detected by the electron transport dependent incorporation of diazonium benzene[35S]sulfo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00691a008
更新日期:1975-10-07 00:00:00
abstract::Drug efflux and enzymatic drug degradation are two cellular mechanisms that contribute to drug resistance in many cancers. Herein, we report the synthesis and in vitro activity of a pro-immunostimulant that exploits both processes in tandem to selectively confer cancer-mediated immunogenicity. We demonstrate that an i...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00095
更新日期:2018-04-17 00:00:00
abstract::Taurine/alpha-ketoglutarate (alphaKG) dioxygenase (TauD), an archetype alphaKG-dependent hydroxylase, is a non-heme mononuclear Fe(II) enzyme that couples the oxidative decarboxylation of alphaKG with the conversion of taurine to aminoacetaldehyde and sulfite. The crystal structure of taurine-alphaKG-Fe(II)TauD is kno...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048746n
更新日期:2005-03-15 00:00:00
abstract::The ras oncogene products (H-Ras, K-Ras, and N-Ras) have been regarded as some of the most promising targets for anticancer drug discovery because their activating mutations are frequently found in human cancers. Nonetheless, molecular targeted therapy for them is currently unavailable. Here, we report the discovery o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00680
更新日期:2018-09-11 00:00:00
abstract::Perturbations within the transactivation and carboxy-terminal domains of HIV-1 Rev were examined for effects on Rev responsive element (RRE) binding activities in vitro and biological activity in vivo. Binding affinities, specificities, and multimerization of the transactivation mutants M10 and Rev/Rex M10-16 on the R...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00085a028
更新日期:1993-08-31 00:00:00
abstract::A fluorescence method is presented for quantitatively analyzing exocytosis phenomena and monitoring their kinetics. The method is based on the particular properties of a hydrophobic fluorescent probe, 1-[4-(trimethylammonio)phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH) [Prendergast, F.G., Haugland, R.P., & Callahan, P.J...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00356a045
更新日期:1986-04-22 00:00:00
abstract::Doublet signal and singlet-like signal induced in Ca(2+)-depleted PS II were investigated by pulsed EPR in one-dimensionally oriented photosystem (PS) II membranes. The doublet signal showed marked angular dependent change in its spectrum in term of the applied magnetic field, indicating that the magnetic dipole-dipol...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9929406
更新日期:2000-09-12 00:00:00
abstract::A detailed characterization of the main chain and side chain dynamics in R. capsulatus ferrocytochrome c(2) derived from (2)H NMR relaxation of methyl group resonances is presented. (15)N relaxation measurements confirm earlier results indicating that R. capsulatus ferrocytochrome c(2) exhibits minor rotational anisot...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0102252
更新日期:2001-06-05 00:00:00
abstract::We have determined the structures of three novel oligosaccharides isolated from human milk using the monoclonal antibody MSW 113. These oligosaccharides were purified by affinity chromatography on a column of the immobilized monoclonal antibody and by high-performance liquid chromatography. From the results of 500-MHz...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00448a031
更新日期:1989-10-31 00:00:00
abstract::Synthetic O-glycopeptides containing one or two GalNAc residues attached to Ser or Thr were used as substrates to investigate the effect of peptide structure on the activity of crude preparations of UDP-Gal:GalNAc alpha-R beta 3-Gal-transferase from pig stomach and pig and rat colonic mucosa and of a partially purifie...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00496a008
更新日期:1990-11-06 00:00:00
abstract::We report an unusually high frequency (543 cm(-)(1)) for an Fe-CO stretching mode in the CO complex of Ascaris suum hemoglobin as compared to vertebrate hemoglobins in which the frequency of the Fe-CO mode is much lower. A second Fe-CO stretching mode in Ascaris hemoglobin is observed at 515 cm(-1). We propose that th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9922087
更新日期:2000-02-01 00:00:00
abstract::This paper describes the effect of N-capping substitutions on the structure and stability of histidine-containing protein (HPr). We have used NMR spectroscopy and conformational stability studies to quantify changes in local and global free energy due to mutagenesis at Ser46, the N-cap for helix B in HPr. Previous NMR...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi960349s
更新日期:1996-09-03 00:00:00
abstract::Apurinic/apyrimidinic endonuclease 1 (APE1) is a DNA repair protein and plays other important roles. Increased levels of APE1 in cancer have been reported. However, available methods for measuring APE1 levels are indirect and not quantitative. We previously developed an approach using liquid chromatography and tandem ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00928
更新日期:2015-09-29 00:00:00
abstract::His12 and His119 are critical for catalysis of RNA cleavage by ribonuclease A (RNase A). Substitution of either residue with an alanine decreases the value of k(cat)/K(M) by more than 10(4)-fold. His12 and His119 are proximal to the scissile phosphoryl group of an RNA substrate in enzyme-substrate complexes. Here, the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0100182
更新日期:2001-04-24 00:00:00
abstract::The structural features of a chemically modified DNA template strand may promote error-prone DNA synthesis during replication. The resulting higher incidence of mutations, in turn, can eventually lead to tumor initiation. Structural insights into this process can be monitored by studying chemically modified base adduc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00046a043
更新日期:1995-11-21 00:00:00
abstract::The temperature dependence of biological rates at different scales (from individual enzymes to isolated organisms to ecosystem processes such as soil respiration and photosynthesis) is the subject of much historical and contemporary research. The precise relationship between the temperature dependence of enzyme rates ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.0c00530
更新日期:2020-09-29 00:00:00
abstract::Acetylcholine receptors have been purified from junctional regions of normal rat diaphragm muscle and from extrajunctional regions of denervated diaphragm. The reaction of purified receptors with [122I]-alpha-bungarotoxin has been investigated by kinetic methods. The toxin-receptor complexes dissociated in a biphasic ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00681a008
更新日期:1975-05-20 00:00:00
abstract::The transcriptional activity of the hexafluorinated derivative of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 [F6-1,25-(OH)2D3], was examined in cultured cells by a transient expression assay (CAT assay) using expression vectors for the rat nuclear vitamin D3 receptor...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00001a045
更新日期:1995-01-10 00:00:00
abstract::Inefficient maturation and trafficking to the cell surface of the cystic fibrosis transmembrane conductance regulator (CFTR) is the primary cause of cystic fibrosis. CFTR protein that fails to mature accumulates as an immature core-glycosylated protein and is rapidly degraded. To determine how the structures of mature...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi992620m
更新日期:2000-04-04 00:00:00
abstract::Phospholipid transfer protein (PLTP) is expressed by macrophage-derived foam cells in human atherosclerotic lesions, suggesting a regulatory role for PLTP in cellular cholesterol homeostasis. However, the exact role of PLTP in the reverse cholesterol transport pathway is not known. PLTP is present in plasma as two for...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700833h
更新日期:2007-10-23 00:00:00