Abstract：
:The thermodynamic parameters characterizing the interaction between rabbit fast skeletal muscle troponin and tropomyosin have been determined at 25 degrees C for three solution conditions: buffer containing (A) 1 mM CaCl2, simulating a "turned-on" state, (B) 3 mM MgCl2, simulating a "turned-off" state, and (C) 2 mM ethylenediaminetetraacetic acid, a reference state. The enthalpies were measured in two buffers with different heats of ionization to allow correction for dissociation or uptake of protons. The enthalpies corrected for proton effects are -22.1, -25.4, and -23.5 kcal/mol, respectively, in buffers A, B, and C. The interaction between troponin and tropomyosin in the presence of calcium is accompanied by release of 0.9 mol of proton per mole of complex. Proton effects in the presence of magnesium and in the absence of divalent metal ions were too small to quantitate. The association constants were measured by using tropomyosin labeled with the extrinsic fluorescent probe dansylaziridine, and binding was detected by enhancement of the probe fluorescence. The magnitudes of the association constants for unlabeled troponin are 7.5 X 10(5), 4.2 X 10(5), and 9.5 X 10(5) M-1, respectively, for the three solution conditions corresponding to unitary free energies of -10.4, -10.1, and -10.6 kcal/mol. The unitary entropies for the interaction are -39, -51, and -43 cal/(deg X mol), respectively, for the three solution conditions. Under these conditions, the troponin-tropomyosin interaction is enthalpy driven, and a large unfavorable entropy must be overcome in the formation of the complex.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Ingraham RH,Swenson CAdoi
10.1021/bi00340a040subject
Has Abstractpub_date
1985-09-10 00:00:00pages
5221-5issue
19eissn
0006-2960issn
1520-4995journal_volume
24pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:The iron storage protein bacterioferritin (Bfr) binds up to 12 hemes b at specific sites in its protein shell. The heme b can be substituted with the photosensitizer Zn(II)-protoporphyrin IX (ZnPP), and photosensitized reductive iron release from the ferric oxyhydroxide {[FeO(OH)] n ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.9b01103
更新日期：2020-04-28 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：:It has been shown by genetic analysis that the external and internal invertases from Saccharomyces cerevisiae share a common structural gene [Taussig, R., & Carlson, M. (1983) Nucleic Acids Res. 11, 1943-1954]. However, the only amino acid composition of these two forms of invertase reported to date has revealed exten...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00343a014
更新日期：1985-10-22 00:00:00
abstract：:This research was undertaken to distinguish between local and global unfolding in the reversible thermal denaturation of bovine pancreatic ribonclease A (RNase A). Local unfolding was monitored by steady-state and time-resolved fluorescence of nine mutants in each of which a single tryptophan was substituted for a wil...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi001945w
更新日期：2001-01-09 00:00:00
abstract：:The mechanisms by which multisubunit histone acetyltransferase (HAT) complexes recognize and perform efficient acetylation on nucleosome substrates are largely unknown. Here, we use a variety of biochemical approaches and compare histone-based substrates of increasing complexity to determine the critical components of...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi602366n
更新日期：2007-02-27 00:00:00
abstract：:In the native purple bacterial reaction center (RC), light-driven charge separation utilizes only the A-side cofactors, with the symmetry related B-side inactive. The process is initiated by electron transfer from the excited primary donor (P*) to the A-side bacteriopheophytin (P* --> P+ H(A)-) in approximately 3 ps. ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi060277x
更新日期：2006-06-13 00:00:00
abstract：:The C-terminal domain from the muscle protein troponin C (TnC) comprises two helix-loop-helix calcium-binding sites (residues 90-162). The assembly of these two sites is governed by calcium binding enabling a synthetic C-terminal domain to be preferentially and stoichiometrically assembled from two synthetic peptides ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi9528006
更新日期：1996-06-11 00:00:00
abstract：:Annexin V is a Ca(2+)-dependent, phospholipid-binding protein that may have one or more membrane-related functions. The binding of annexin V to phospholipids in a detergent micelle matrix was studied to attempt to determine directly the stoichiometry of specific phospholipid-binding sites and the importance of negativ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00094a030
更新日期：1993-11-02 00:00:00
abstract：:F(1)-ATPase mutations in Escherichia coli that changed the strength of hydrogen bonds between the alpha and beta subunits in a location that links the catalytic site to the interface between the beta catch loop and the gamma subunit were examined. Loss of the ability to form the hydrogen bonds involving alphaS337, bet...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi052592+
更新日期：2006-09-19 00:00:00
abstract：:There are highly conserved hydrogen bonds between the distal His and the adjacent Asn in many peroxidases. Although the crystal structure of horseradish peroxidase C (HRP) is not available, comparison of the amino acid sequence with cytochrome c peroxidase indicates that Asn70 is making the hydrogen bond with the dist...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi961740g
更新日期：1996-11-12 00:00:00
abstract：:Diethyl pyrocarbonate inhibited diaphorase activity of ferredoxin-NADP+ oxidoreductase with a second-order rate constant of 2 mM-1 X min-1 at pH 7.0 and 20 degrees C, showing a concomitant increase in absorbance at 242 nm due to formation of carbethoxyhistidyl derivatives. Activity could be restored by hydroxylamine, ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00294a031
更新日期：1983-12-06 00:00:00
abstract：:By use of a mutational assay employing an octadecamer with a mismatch in the center, it is shown that the introduction of phosphorothioate groups near the 5'-end can protect the mismatch against degradation by the 5'-3'-exonuclease activity of Escherichia coli DNA polymerase I. An optimal level of protection is achiev...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00399a032
更新日期：1987-12-15 00:00:00
abstract：:Understanding the structural basis for defects in protein function that underlie protein-based genetic diseases is the fundamental requirement for development of therapies. This situation is epitomized by the cystic fibrosis transmembrane conductance regulator (CFTR)-the gene product known to be defective in CF patien...
journal_title：Biochemistry
pub_type： 杂志文章,评审
doi：10.1021/bi702209s
更新日期：2008-02-12 00:00:00
abstract：:Pyrroloquinoline quinone (PQQ) is a small, redox active molecule that serves as a cofactor for several bacterial dehydrogenases, introducing pathways for carbon utilization that confer a growth advantage. Early studies had implicated a ribosomally translated peptide as the substrate for PQQ production. This study pres...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi201763d
更新日期：2012-03-20 00:00:00
abstract：:Ultrafast laser spectroscopy techniques are used to measure the low-frequency vibrational coherence spectra and nitric oxide rebinding kinetics of Caldariomyces fumago chloroperoxidase (CPO). Comparisons of the CPO coherence spectra with those of other heme species are made to gauge the protein-specific nature of the ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi7025485
更新日期：2008-05-06 00:00:00
abstract：:The specific effect of the binding of IF2 and initiator fMET-tRNA(fMet) on Escherichia coli 16S rRNA has been probed by phosphate alkylation with ethylnitrosourea. The results show that IF2 does not significantly shield portions of 16S rRNA but induces both reductions and enhancements of reactivity scattered in the en...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00487a023
更新日期：1990-09-04 00:00:00
abstract：:The ileal apical and liver basolateral bile acid transporters catalyze the Na+-dependent uptake of these amphipathic molecules in the intestine and liver. They contain nine predicted helical hydrophobic sequences (H1-H9) between the exoplasmic N-glycosylated N terminus and the cytoplasmic C terminus. Previous in vitro...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi051291x
更新日期：2005-10-25 00:00:00
abstract：:The structure of premature core enzyme, an obligatory intermediate in both in vivo and in vitro assembly of Escherichia coli DNA-dependent RNA polymerase, was compared with that of native core enzyme. Though this assembled but inactive form of core enzyme harbors the gross conformation similar to that of native enzyme...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00573a006
更新日期：1979-03-20 00:00:00
abstract：:It is known that the overall charge of a protein can change as the molecule approaches a charged object like another protein or a cell membrane. We have formalized this mechanism using a statistical mechanical framework and show how this rather overlooked interaction increases the attraction between protein molecules....
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi047630o
更新日期：2005-04-19 00:00:00
abstract：:Proteogenomic identification of translated small open reading frames in humans has revealed thousands of microproteins, or polypeptides of fewer than 100 amino acids, that were previously invisible to geneticists. Hundreds of microproteins have been shown to be essential for cell growth and proliferation, and many reg...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/acs.biochem.0c00672
更新日期：2020-10-27 00:00:00
abstract：:A series of antisense oligonucleotides (ASOs) were synthesized and tested to define the best target sites within an RNA transcript of collagen for effective inhibition of expression. The test system consisted of mouse NIH 3T3 fibroblasts that were stably transfected with a human minigene for procollagen I so that the ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00202a024
更新日期：1994-09-13 00:00:00
abstract：:Biotin synthase catalyzes the conversion of dethiobiotin (DTB) to biotin through the oxidative addition of sulfur between two saturated carbon atoms, generating a thiophane ring fused to the existing ureido ring. Biotin synthase is a member of the radical SAM superfamily, composed of enzymes that reductively cleave S-...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi201042r
更新日期：2011-09-20 00:00:00
abstract：:Cytochrome c has been chemically modified by methylene blue mediated photooxidation. It is established that the methionine residues of the protein have been specifically converted to methionine sulfoxide residues. No oxidation of any other amino acid residues or the cysteine thioether bridges of the molecule occurs du...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00650a029
更新日期：1976-03-09 00:00:00
abstract：:Twelve site-directed mutants of rat cytochrome P450 2B1 distributed over seven positions and four putative substrate recognition sites (SRS) were constructed and expressed in COS cells. Function was examined using androstenedione and testosterone as substrates. Substitutions at positions 303, 360, and 473 did not mark...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00180a040
更新日期：1994-04-12 00:00:00
abstract：:Excitation energy transfer and trapping processes in an iron stress-induced supercomplex of photosystem I from the cyanobacterium Synechocystis sp. PCC6803 were studied by time-resolved absorption and fluorescence spectroscopy on femtosecond and picosecond time scales. The data provide evidence that the energy transfe...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi026987u
更新日期：2003-04-08 00:00:00
abstract：:Membrane-bound mammalian adenylyl cyclase isoforms contain two internally homologous cytoplasmic domains (C1 and C2). When expressed separately, C1 and C2 are catalytically inactive, but conversion of ATP to cAMP is observed if C1 and C2 are combined. By analogy with DNA polymerases, adenylyl cyclases are thought to r...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi981441m
更新日期：1998-11-17 00:00:00
abstract：:HTC cells have been labeled by short exposures to [3H]thymidine in order to identify newly synthesized DNA. By either isolating nuclei directly or isolating them after an extensive fixation with formaldehyde, we have been able to identify two phases in the maturation process of newly replicated chromatin. The first ph...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00302a036
更新日期：1984-03-27 00:00:00
abstract：:The tyrosine kinase c-Abl is implicated in a variety of cellular processes that are tightly regulated by c-Abl kinase activity and/or by interactions between c-Abl and other signaling molecules. The interaction of c-Abl with the Abl interactor protein Abi2 is shown to be negatively regulated by phosphorylation of seri...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi701533j
更新日期：2008-01-22 00:00:00
abstract：:A heterologous expression system was used to evaluate activation of BlaR1, a sensor/signal transducer protein of Staphylococcus aureus with a central role in resistance to β-lactam antibiotics. In the absence of other S. aureus proteins that might respond to antibiotics and participate in signal transduction events, w...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi300429p
更新日期：2012-06-12 00:00:00
abstract：:Structural and genetic studies indicate that the antibacterial compound triclosan, an additive in many personal care products, is an inhibitor of EnvM, the enoyl reductase from Escherichia coli. Here we show that triclosan specifically inhibits InhA, the enoyl reductase from Mycobacterium tuberculosis and a target for...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0008940
更新日期：2000-07-04 00:00:00
