Abstract:
:We have carried out a comparative study of the effect of cholesterol on the thermotropic phase behavior of the distearoyl and dielaidoyl molecular species of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine using high-sensitivity differential scanning calorimetry. For both molecular species of phosphatidylcholine, cholesterol incorporation produces bimodal endotherms at lower and unimodal endotherms at higher sterol concentrations. In both cases, heating and cooling endotherms are identical, and high concentrations of cholesterol (50 mol %) completely abolish the gel to liquid-crystalline phase transition. For the distearoyl molecular species of phosphatidylserine and phosphatidylethanolamine, heating and cooling endotherms are not identical, and cholesterol exhibits a considerably reduced miscibility in the gel as compared to the liquid-crystalline phase, particularly in the latter case. Thus, in neither case does the addition of 50 mol % cholesterol completely abolish the cooperative hydrocarbon chain-melting phase transition. However, the dielaidoyl molecular species of phosphatidylserine and phosphatidylethanolamine exhibit much closer correspondence in the heating and cooling modes than do the distearoyl species, and 50 mol % cholesterol is sufficient to almost or completely abolish the gel to liquid-crystalline phase transition of dielaidoylphosphatidylethanolamine and dielaidoylphosphatidylserine. In general, there is an inverse correlation between the strength of intermolecular phospholipid-phospholipid interactions, as manifested by the relative gel to liquid-crystalline phase transition temperatures of the pure phospholipids, and the miscibility of cholesterol in bilayers, particularly gel-state bilayers, formed from these phospholipids. These results indicate that the nature of cholesterol-phospholipid interactions, and thus the miscibility of cholesterol in the bilayer, depends on both the structure of the phospholipid polar headgroup and the hydrocarbon chains, as well as on the temperature and phase state of the phospholipid bilayer.
journal_name
Biochemistryjournal_title
Biochemistryauthors
McMullen TP,McElhaney RNdoi
10.1021/bi962815jsubject
Has Abstractpub_date
1997-04-22 00:00:00pages
4979-86issue
16eissn
0006-2960issn
1520-4995pii
bi962815jjournal_volume
36pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::We investigated the effects of substituting two of the four tryptophans (the "inner pair" Trp(9) and Trp(11) or the "outer pair" Trp(13) and Trp(15)) in gramicidin A (gA) channels. The conformational preferences of the doubly substituted gA analogues were assessed using circular dichroism spectroscopy and size-exclusi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200136e
更新日期:2011-06-07 00:00:00
abstract::The DNA repair enzyme uracil DNA glycosylase has been crystallized with a cationic 1-aza-2'-deoxyribose-containing DNA that mimics the ultimate transition state of the reaction in which the water nucleophile attacks the anomeric center of the oxacarbenium ion-uracil anion reaction intermediate. Comparison with substra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035372+
更新日期:2003-11-04 00:00:00
abstract::It is known that aconitase from mammalian mitochondria is only partially active as isolated but may be activated by incubation with iron, ascorbate, and a thiol, or with dithionite. It has been suggested that the added Fe in the activation mixture is essential for activation and that it is incorporated in the enzyme [...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00529a023
更新日期:1981-12-22 00:00:00
abstract::Amyloid diseases are caused by the self-assembly of a given protein into an insoluble cross-beta-sheet quaternary structural form which is pathogenic. An understanding of the biochemical mechanism of amyloid fibril formation should prove useful in understanding amyloid disease. Toward this end, a procedure for the con...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00151a036
更新日期:1992-09-15 00:00:00
abstract::The DNA of Novikoff hepatoma ascites cells was found to contain a 3.6-megadalton EcoRI restriction fragment, referred to as EcoRI fragment A (Parker et al., 1979). C0t analyses demonstrated an enrichment of fragment A sequences in Novikoff hepatoma genome relative to normal rat liver DNA. This fragment was cloned in l...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00507a017
更新日期:1981-02-17 00:00:00
abstract::Despite significant progress in the past decade, questions still remain about the complete structural, dynamic, and thermodynamic effect of the cis-syn cyclobutane pyrimidine dimer lesion (hereafter called the thymine dimer) on double-stranded genomic DNA. We examined a 19-mer oligodeoxynucleotide duplex containing a ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi801417u
更新日期:2008-12-09 00:00:00
abstract::The peptides generated from the degradation of the oxidized B chain of bovine insulin by the multiproteinase complex macropain (proteasome) have been analyzed by reverse-phase peptide mapping and identified by N-terminal amino acid sequencing and composition analysis. Six of the 29 peptide bonds in the insulin B chain...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00224a022
更新日期:1991-03-12 00:00:00
abstract::Ryanodine receptor (RyR) mutations linked with some congenital skeletal and cardiac diseases are localized to three easily definable regions: region 1 (N-terminal domain), region 2 (central domain), and a rather broad region 3 containing the channel pore. As shown in our recent studies, the interdomain interaction bet...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061557f
更新日期:2007-04-10 00:00:00
abstract::The NikR transcription factor from Escherichia coli is a Ni(II)-dependent repressor that regulates production of the nickel ion transporter encoded by the nik operon. In the previous paper in this issue (Wang, S. C., Dias, A., Bloom, S. L., and Zamble, D. B. (2004) Selectivity of Metal Binding and Metal-Induced Stabil...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049404k
更新日期:2004-08-10 00:00:00
abstract::Raman spectra of phycocyanobilin, phycocyanin, and allophycocyanin were obtained at resonance with their visible and near-UV transitions. These spectra were empirically assigned with the help of 14N- and 15N-isotopic substitutions and comparisons with resonance Raman spectra of phycoerythrin. These results confirm the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00205a019
更新日期:1994-10-04 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 structure of the ca. 250 amino acid hormone binding domain of the human estrogen receptor (hER-LBD), expressed in E. coli and purified as a complex with estradiol, has been probed by selective proteolysis, with analysis of the protein fragments both by classical methods (SDS-PAGE and Edman N-terminal sequencing) a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00039a016
更新日期:1995-10-03 00:00:00
abstract::Electron-transfer reactions following the formation of P700(+)A1- have been studied in isolated Photosystem I complexes from Synechococcus elongatus between 300 and 5 K by flash absorption spectroscopy. (1) In the range from 300 to 200 K, A1- is reoxidized by electron transfer to the iron-sulfur cluster FX. The rate s...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi973182r
更新日期:1998-06-30 00:00:00
abstract::The crystal structure of the catalytic domain of rat DNA polymerase beta revealed that Asp256 is located in proximity to the previously identified active site residues Asp190 and Asp192. We have prepared and kinetically characterized the nucleotidyl transfer activity of wild type and several mutant forms of human and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00049a008
更新日期:1995-12-12 00:00:00
abstract::Two novel heme-containing peroxidases, one able to incorporate halogens into aromatic substrates and the other able to remove them, have recently been isolated from marine sources and initially characterized by Chen et al. [(1991) J. Biol. Chem. 266, 23909-23915; (1996) J. Biol. Chem. 271, 4609-4612]. The haloperoxida...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9621371
更新日期:1997-02-25 00:00:00
abstract::A covalent dimer of Saccharomyces cerevisiae iso-1 cytochrome c is stabilized by an interchain disulfide bond involving the cysteine residue penultimate to the C-terminus. The individual chains in the dimer appear to retain the tertiary structural features characteristic for monomeric cytochrome c albeit with some per...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00335a011
更新日期:1985-07-02 00:00:00
abstract::Incorporation of nonproteinogenic amino acids in small polypeptides synthesized by nonribosomal peptide synthetases (NRPS) significantly contributes to their biological activity. In these peptides, conversion of L-amino acids to the corresponding D-isomer is catalyzed by specialized NRPS modules that utilize an epimer...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011595t
更新日期:2001-12-25 00:00:00
abstract::The chemical mechanism of the phosphoribosyltransferases (PRTases), although largely unknown, may proceed either via a concerted direct-transfer mechanism or with a two-step mechanism involving a carboxonium-like intermediate. To study this question, we have cloned the Salmonella typhimurium pyrE gene, coding for the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00498a009
更新日期:1990-11-20 00:00:00
abstract::Tafazzin is the mitochondrial enzyme that catalyzes transacylation between a phospholipid and a lysophospholipid in remodeling. Mutations in tafazzin cause Barth syndrome, a potentially life-threatening disease with the major symptom being cardiomyopathy. In the tafazzin-deficient heart, cardiolipin (CL) acyl chains b...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00042
更新日期:2018-04-10 00:00:00
abstract::The activation of adenosine-5'-monophosphate aminohydrolase from rabbit skeletal muscle by H+ has been demonstrated. Evidence is presented which indicates that the binding of H+ and K+ is linked, in that the dissociation constant (KA) for K+ activation is reduced as the pH is lowered. Concomitantly, the pK of several ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00641a013
更新日期:1977-11-01 00:00:00
abstract::Time-resolved resonance Raman (TR(3)) and time-resolved step-scan (TRS(2)) FTIR spectroscopies have been used to probe the structural dynamics at the heme b(3) proximal and distal sites after carbon monoxide photolysis from fully reduced CO-bound nitric oxide reductase. The Raman spectra of the transient species exhib...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035289m
更新日期:2003-12-23 00:00:00
abstract::4-Oxalocrotonate tautomerase (4-OT) and YwhB, a 4-OT homologue found in Bacillus subtilis, exhibit a low level hydratase activity that converts trans-3-haloacrylates to acetaldehyde, presumably through a malonate semialdehyde intermediate. The mechanism for the initial transformation of the 3-haloacrylate to malonate ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035495u
更新日期:2004-01-27 00:00:00
abstract::The cytochrome bc(1) complex from Paracoccus denitrificans and soluble fragments of its cytochrome c(1) and Rieske ISP subunits are characterized by a combined approach of protein electrochemistry and FTIR difference spectroscopy. The FTIR difference spectra provide information about alterations in the protein upon re...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035103j
更新日期:2003-10-28 00:00:00
abstract::The first step in sulfur mobilization for the biosynthesis of Fe-S clusters under oxidative stress and iron starvation in Escherichia coli involves a cysteine desulfurase SufS. Its catalytic reactivity is dependent on the presence of a sulfur acceptor protein, SufE, which acts as the preferred substrate for this enzym...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi4001479
更新日期:2013-06-11 00:00:00
abstract::The molecular mass (M(r)) of the nickel- and iron-sulfur-containing enzyme CO dehydrogenase from Clostridium thermoaceticum was determined by sedimentation equilibrium ultracentrifugation to be 300,000 +/- 30,000 Da. Since the enzyme is known to contain equal numbers of two types of subunits (M(r) = 82,000 Da for alph...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9511853
更新日期:1996-02-13 00:00:00
abstract::Aminoimidazole riobnucleotide carboxylase, the sixth step in the purine biosynthetic pathway, catalyzes the conversion of aminoimidazole ribonucleotide (AIR) to carboxyaminoimidazole ribonucleotide (CAIR). The gene products of the purE and purK genes (PurE and PurK, respectively) thought to be responsible for this act...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00136a016
更新日期:1992-06-02 00:00:00
abstract::Nitrobenzamido ligands linked to the DNA intercalator 9-aminoacridine via poly(methylene) chains induce single-strand nicks in DNA upon irradiation with long-wavelength ultraviolet light (lambda greater than or equal to 300 nm). Optimal photocleavage activity was found for the reagent 9-[[6-(4-nitrobenzamido)hexyl]ami...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00417a021
更新日期:1988-08-23 00:00:00
abstract::The temperature dependence of steady-state kinetics has been studied with horse liver alcohol dehydrogenase (HLADH) using protonated and deuterated benzyl alcohol as substrates in methanol/water mixtures between +3 and -50 degrees C. Additionally, the competitive isotope effects, k(H)/k(T) and k(D)/k(T), were measured...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002075l
更新日期:2001-02-20 00:00:00
abstract::The clathrin assembly protein complex AP-2 is a multimeric subunit complex consisting of two 100-115-kDa subunits known as alpha and beta and 50- and 16-kDa subunits. The subunits have been dissociated and separated by ion-exchange chromatography in 7.5 M urea. Fractions highly enriched in either the alpha or beta sub...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00236a036
更新日期:1991-06-04 00:00:00
abstract::It has been suggested that dimeric tubulin can participate in the signal transduction process through its association with the GTP-binding (G) proteins Gs and Gi1. Using the photoaffinity GTP analog, azidoanilido-GTP, it has been shown that the transfer of nucleotide from tubulin to G alpha s and G alpha i1 is the key...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00198a052
更新日期:1994-08-16 00:00:00