Abstract:
:The binding of ethidium bromide, as monitored by fluorescence enhancement, to chromatin prepared by nuclease digestion has been compared with the binding of the dye to sheared chromatin. The nuclease preparation (native chromatin) is characterized by a high affinity region of the Scatchard plot (r = 0-0.025, K1 = 1 X 10(6) M-1), a transition (r = 0.025-0.05), and a low affinity region (r = 0.05-0.12, K2 = 3 X 10(5) M-1). The final amount of ethidium bromide bound per base is 0.12 as compared with 0.20 for free DNA. Sheared chromatin has the two regions of high and low affinity (K1 = 2 X 10(6) M-1, K2 = 5 X 10(5) M-1) as originally shown by Angerer and Moudrianakis (1972), but the transition is much reduced or absent. Binding of the dye to native chromatin is independent of salt at concentrations ranging from 0.2 mM EDTA to 10 mM Tris-Cl, 10 mM NaCl, 0.2 mM EDTA, while sheared chromatin and DNA both bind ethidium bromide electrostatically as well as by intercalation at the low salt concentration, leading to extensive energy transfer. Thus the phosphate groups in native chromatin are unavailable to external cations even at very low salt. Polarization of fluorescence of ethidium bromide intercalated into native chromatin at low r is very high, indicating a highly rigid structure. As r approaches 0.02, there is a very rapid depolarization; at r = 0.03, the polarization is no greater than that of the dye intercalated into DNA. Depolarization is not due to energy transfer. The Scatchard plot derived for the bulk preparation of native chromatin is very similar to the one derived for the monomer nu body. These results indicate that the DNA in native chromatin is in a very rigid form, with its phosphate anions neutralized by structural components, not by free salt. Ethidium bromide intercalation appears partially to disrupt this structure, perhaps by unwinding, leading to slight changes in its properties.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Paoletti J,Magee BB,Magee PTdoi
10.1021/bi00622a002subject
Has Abstractpub_date
1977-02-08 00:00:00pages
351-7issue
3eissn
0006-2960issn
1520-4995journal_volume
16pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::The misfolding of amyloid beta (Aβ) is one of the predominant hallmarks in the pathology of Alzheimer's disease (AD). In this study, we showed that the formation of the Aβ ion channel on the membrane depended on the cholesterol concentration. From a mechanical aspect, we found that cholesterol levels affected the stab...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.9b00968
更新日期:2020-03-03 00:00:00
abstract::The chromatin-associated high-mobility group (HMG) proteins of the plant HMGB family are characterized by a central HMG-box domain that is flanked by a basic N-terminal and an acidic C-terminal domain. By functional interaction with certain transcription factors, HMGB proteins contribute to transcriptional regulation....
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi6024947
更新日期:2007-05-29 00:00:00
abstract::The experiments described here explore the role of local sequence in the folding of cellular retinoic acid binding protein I (CRABP I). This is a 136-residue, 10-stranded, antiparallel beta-barrel protein with seven beta-hairpins and is a member of the intracellular lipid binding protein (iLBP) family. The relative ro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034304k
更新日期:2003-07-08 00:00:00
abstract::Large conductance Ca(2+)-activated K(+) channels (BK(Ca)) contain an intracellular binding site for bovine pancreatic trypsin inhibitor (BPTI), a well-known inhibitor of various serine proteinase (SerP) enzymes. To investigate the structural basis of this interaction, we examined the activity of 11 BPTI mutants using ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi992140v
更新日期:2000-02-29 00:00:00
abstract::The crystal structure of a human carbonic anhydrase II (CAII) variant, cis-proline-202-->alanine (P202A), has been determined at 1.7-A resolution, indicating that the wild-type geometry, including the cis-peptidyl linkage, is retained upon substitution of proline by alanine. The CO2 hydrase activity and affinity for s...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00092a003
更新日期:1993-10-19 00:00:00
abstract::An antibody population that reacted with the high-affinity lysine binding site of human plasminogen was elicited by immunizing rabbits with an elastase degradation product containing kringles 1-3 (EDP I). This antibody was immunopurified by affinity chromatography on plasminogen-Sepharose and elution with 0.2 M 6-amin...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00370a028
更新日期:1986-11-04 00:00:00
abstract::In the presence of Ca2+ norchlorpromazine isothiocyanate forms a monocovalent complex with calmodulin: CAPP1-calmodulin (Newton et al, 1983). Trypsin digestion of [3H]CAPP1-calmodulin yields as the major radioactive peptide N epsilon-CAPP-Lys-Met-Lys, corresponding to residues 75-77 of calmodulin. Stoichiometric amoun...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00435a019
更新日期:1989-05-02 00:00:00
abstract::The Escherichia coli L-arabinose-binding protein (ABP) participates as a specific receptor in the transport of L-arabinose, D-fucose, and D-galactose through the periplasmic space. The wild-type protein binds L-arabinose about 40 times more strongly than D-fucose. A mutation of the protein at position 108 (Met-->Leu) ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00080a013
更新日期:1993-07-27 00:00:00
abstract::The Wiskott-Aldrich syndrome protein (WASP) and neural WASP (N-WASP) are key players in regulating actin cytoskeleton via the Arp2/3 complex. It has been widely reported that the WASP proteins are activated by Rho family small GTPase Cdc42 and that Rac1 acts through SCAR/WAVE proteins. However, a systematic study of t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi062152y
更新日期:2007-03-20 00:00:00
abstract::Using heteronuclear NMR spectroscopy, we demonstrate that a 13-residue peptide (MS-QIKRLLSEKKT) from the cytoplasmic tail of CD4 binds to Nef protein. This part of CD4 is critical for downregulation of CD4 by HIV-1 Nef [Aiken et al. (1994) Cell 76, 853-864]. We show that a control peptide without the central dileucine...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9611164
更新日期:1996-08-13 00:00:00
abstract::Nonribosomal peptide synthetases (NRPSs) are megasynthetases that require complex and specific interactions between multiple domains and proteins to functionally produce a metabolite. MbtH-like proteins (MLPs) are integral components of many NRPSs and interact directly with the adenylation domain of the megasynthetase...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00552
更新日期:2018-07-17 00:00:00
abstract::Three different cleavable photoactivable heterobifunctional reagents have been synthesized and characterized by proton NMR, 13C NMR, mass spectroscopy, infrared spectroscopy, and thin-layer chromatography. They are the N-hydroxysuccinimide ester of 3-[(4-azidophenyl)dithio]-propionic acid, methyl 3-[(4-azidophenyl)dit...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00527a003
更新日期:1981-11-24 00:00:00
abstract::In reticulocytes, a single ribosomal protein, S13, has been shown to be phosphorylated by the cAMP-regulated protein kinases. The 40S ribosomal subunits were phosphorylated in vitro with [gamma-32P]ATP to facilitate the identification of S13 during the two-step purification procedure. Total ribosomal protein from the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00604a003
更新日期:1978-05-30 00:00:00
abstract::The nucleotide binding capacity and affinity of the isolated beta subunit from Escherichia coli F1-ATPase have been studied with radiolabeled ADP and ATP by an equilibrium dialysis technique. Each mole of beta subunit in the presence of EDTA bound 1 mol of ADP or ATP with Kd values of 25 microM and 50-100 microM, resp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00321a048
更新日期:1984-12-18 00:00:00
abstract::The fungal metabolite gliotoxin has a redox-active disulfide bridge spanning carbons 3 and 6 of a diketopiperazine (DKP) scaffold. The proposed DKP synthetase, GliP, from Aspergillus fumigatus Af293, is a three module (A1-T1-C1-A2-T2-C2-T3) 236 kDa protein that can be overproduced in soluble form in Escherichia coli. ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061845b
更新日期:2006-12-19 00:00:00
abstract::Among the 118 genes upregulated by Pseudomonas aeruginosa in response to iron starvation [Ochsner, U. A., Wilderman, P. J., Vasil, A. I., and Vasil, M. L. (2002) Mol. Microbiol. 45, 1277-1287], we focused on the products of the two genes encoding electron transfer proteins, as a means of identifying the redox partners...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi7013135
更新日期:2007-10-30 00:00:00
abstract::The importance of the evolutionarily conserved Gly-4 residue for the affinity and kinetics of interaction of cystatin A with several cysteine proteinases was assessed by site-directed mutagenesis. Even the smallest replacement, by Ala, resulted in approximately 1000-, approximately 10- and approximately 6000-fold decr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi980026r
更新日期:1998-05-19 00:00:00
abstract::NMR spectroscopic experiments were performed to study the structure of synthetic peptides identical to two extracellular regions of the human thrombin receptor. The smaller molecule, comprising 14 amino acids, was biologically active and was equivalent to the "tethered ligand" exposed after cleavage of the receptor by...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00186a005
更新日期:1994-05-24 00:00:00
abstract::The kinetic and equilibrium CO binding properties of hemoglobin (Hb) M Iwate (alpha2 87 His leads to Tyr beta2) have been investigated. The results show that the alpha(Met) beta2 (CO) tetramer of this protein has a low affinity for CO, as indicated by the stopped-flow and flash-photolysis kinetic, as well as the CO bi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00669a022
更新日期:1976-11-30 00:00:00
abstract::Intrinsically disordered proteins (IDPs) are functionally active despite lacking a well-defined three-dimensional structure. Such proteins often undergo a disorder-to-order transition, or induced folding, when binding to their specific physiological partner. Because of cooperativity, the folding and binding steps typi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b00350
更新日期:2017-07-25 00:00:00
abstract::The three-dimensional solution structure of the repeating -PO4-6Gal beta 1-4Man alpha 1- disaccharide fragment of the lipophosphoglycan (LPG) derived from Leishmania donovani has been determined by use of a combination of homo- and heteronuclear NMR spin coupling constant measurements together with restrained molecula...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00118a004
更新日期:1992-01-28 00:00:00
abstract::Biotin synthase (BioB) is an iron-sulfur dimeric enzyme which catalyzes the last step in biotin synthesis. The reaction consists of the introduction of a sulfur atom into dethiobiotin. It is shown here that BioB displays a significant cysteine desulfurase activity, providing it with the ability to mobilize sulfur from...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0122011
更新日期:2002-07-23 00:00:00
abstract::Two-dimensional homonuclear and heteronuclear NMR and minimized potential energy calculations have been combined to define the structure of the antitumor agent mitomycin C (MC) cross-linked to deoxyguanosines on adjacent base pairs in the d(T1-A2-C3-G4-T5-A6).d(T7-A8-C9-G10-T11-A12) duplex. The majority of the mitomyc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00463a032
更新日期:1990-03-20 00:00:00
abstract::Nuclear DNA of the marine chromophytic alga Olisthodiscus luteus was analyzed in this study. Reassociation kinetics analysis has shown that 440-nucleotide DNA fragments from the genome of this alga contain 4% foldback, 58% repetitive, and 34% single-copy sequences. Precise analysis using isolated single-copy DNA revea...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00527a023
更新日期:1981-11-24 00:00:00
abstract::The rotational motions of immunoglobulin M (IgM) were investigated by the nanosecond fluorescence depolarization technique. The fluorophore epsilon-1-dimethylamino-5-naphthalenesulfonyl-L-lysine (DNS-lysine) was specifically bound in the combining sites of anti-DNS IgM antibodies from the horse, pig, and nurse shark. ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00660a033
更新日期:1976-07-27 00:00:00
abstract::Recent studies showed that p34(SEI-1), also known as TRIP-Br1 or SEI-1, plays a dual role in the regulation of cell-cycle progression. It exhibits the transactivation activity and regulates a number of genes required for G1/S transition, while it also binds and activates cyclin-dependent kinase 4 (CDK4) independent of...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0504658
更新日期:2005-10-11 00:00:00
abstract::Stopped-flow experiments obtained in the pre-steady-state time scale of the NAD-malic enzyme reaction exhibit a lag prior to the attainment of steady state. Previous results from isotope effect studies in which the deuterium isotope effect on Vmax decreases to a value of 1 at low pH have been interpreted as suggesting...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00059a007
更新日期:1993-03-02 00:00:00
abstract::PsbU is a lumenal peripheral protein in the photosystem II (PS II) complex of cyanobacteria and red algae. It is thought that PsbU is replaced functionally by PsbP or PsbQ in plant chloroplasts. After the discovery of PsbP and PsbQ homologues in cyanobacterial PS II [Thornton et al. (2004) Plant Cell 16, 2164-2175], w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi047539k
更新日期:2005-09-13 00:00:00
abstract::Chloride intracellular channel protein 1 (CLIC1) functions as an anion channel in plasma and nuclear membranes when its soluble monomeric form converts to an integral-membrane form. The transmembrane region of CLIC1 is located in its thioredoxin-like domain 1, but the mechanism whereby the protein converts to its memb...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9010607
更新日期:2009-09-08 00:00:00
abstract::The human transferrin receptor (TfR) has three N-linked oligosaccharides. A combination of site-directed mutagenesis and carbohydrate and protein chemistry was used to characterize the structures of the N-linked oligosaccharides and to map their locations. We find that the type of oligosaccharide at each position was ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962884y
更新日期:1997-04-29 00:00:00