Abstract:
:The molecular organization of sterols in liposomes of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at 37 degrees C is examined by utilizing the fluorescent analogue of cholesterol cholesta-5,7,9-trien-3 beta-ol (cholestatrienol). (1) Cholestatrienol is shown to be indistinguishable from native cholesterol in terms of its ability to condense POPC, as determined by (i) pressure/area studies of mixed-lipid monolayers and (ii) its ability to increase the order of POPC bilayers (determined by electron spin resonance studies) whether on its own or admixed with cholesterol at various ratios. (2) By analysis of the perturbation of the absorption spectra, cholestatrienol was found to be freely miscible in aggregates of cholesterol in buffer. In contrast, a lack of any detectable direct interaction of the sterol molecules in POPC bilayers was detected. (3) Fluorescence intensity and lifetime measurements of POPC/sterol (1:1 mol/mol) at various cholesterol/cholestratrienol molar ratios (0.5:1 up to 1:1 cholestatrienol/POPC) confirmed that sterol molecules in the membrane matrix were not associated to any great degree. (4) A quantitative estimate of how close sterol molecules approach each other in the membrane matrix was evaluated from the concentration dependence of the steady-state depolarization of fluorescence and was found to be 10.6 A. From geometrical considerations, the sterol/phospholipid phase at 1:1 mol/mol is depicted as each sterol having four POPC molecules as nearest neighbors. We term this arrangement of the lipid matrix an "ordered bimolecular mesomorphic lattice". (5) The concentration dependence of depolarization of fluorescence of cholestatrienol in POPC liposomes in the absence of cholesterol yielded results that were consistent with the cholestatrienol molecules being homogeneously dispersed throughout the phospholipid phase at sterol/POPC ratios of less than 1:1. (6) From qualitative calculations of the van der Walls' hydrophobic interactions of the lipid species, the phospholipid condensing effect of cholesterol is postulated to arise from increased interpenetration of the flexible methylene segments of the acyl chains, as a direct result of their greater mutual attraction compared to their attraction for neighboring sterol molecules. (7) The interdependence of the ordered bimolecular mesomorphic lattice and the acyl chain condensation is discussed in an effort to understand the ability of cholesterol to modulate the physical and mechanical properties of biological membranes.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Hyslop PA,Morel B,Sauerheber RDdoi
10.1021/bi00456a027subject
Has Abstractpub_date
1990-01-30 00:00:00pages
1025-38issue
4eissn
0006-2960issn
1520-4995journal_volume
29pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Double homeodomain (DUX) proteins are encoded by a family of 3.3-kilobase repeated elements dispersed in the human genome. One of these elements named D4Z4 is found in a tandem repeat array on chromosome 4 that is partially deleted in facioscapulohumeral muscular dystrophy. We have evaluated the trafficking and mobili...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi047992w
更新日期:2005-02-22 00:00:00
abstract::The following peptide was synthesized by classical methods in solution: Ac-Asp-Phe-Leu-Ala-Glu-Gly-Gly-Gly-Val-Arg-Gly-Pro-Arg-Val-NHCH3 (F-8). The Michaelis-Menten parameters for the hydrolysis of the Arg-Gly bond in F-8 by thrombin were determined to be Kcat = 31 X 10(-11) M [(NIH unit/L) s]-1 and KM = 310 X 10(-6) ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00287a002
更新日期:1983-08-30 00:00:00
abstract::Glycerol stabilizes the triple-helical structure of solubilized calf skin collagen. The equilibrium melting temperature of the protein increased linearly from 38.0 degrees C in AS buffer (0.01 M NaOAc and 0.02 M NaCl, pH 4.0) to 43.0 degrees C in AS and 6 M glycerol buffer. To understand the thermodynamic basis of thi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00353a004
更新日期:1986-03-11 00:00:00
abstract::Ketosteroid isomerase (KSI) is one of the most proficient enzymes catalyzing an allylic isomerization reaction at a diffusion-controlled rate. In this study of KSI, we have detailed the structures of its active site, the role of various catalytic residues, and have explained the origin of the its fast reactivity by ca...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi001629h
更新日期:2000-11-14 00:00:00
abstract::A human cDNA, UDPGTh-3, encoding a dihydrotestosterone/5 alpha-androstane-3 alpha,17 beta-diol UDP- glucuronosyltransferase (transferase) has been isolated and characterized. The nucleotide sequence of UDPGTh-3 encodes a 530 amino acid protein with a typical membrane insertion-signal peptide, a membrane-anchoring doma...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00091a015
更新日期:1993-10-12 00:00:00
abstract::Atlantic salmon fast skeletal muscle is composed of an α-type tropomyosin that shares 20 substitutions with a mammalian homologue. Prominent isomorphisms considered to be potentially destabilizing include threonine 179 (core, Ala in rabbit) and a unique pair of glycines, residues 24 and 27. Bacterially expressed mutan...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00156
更新日期:2015-05-05 00:00:00
abstract::Site-directed mutations R177A and R177K in the gene encoding manganese peroxidase isozyme 1 (mnp1) from Phanerochaete chrysosporium were generated. The mutant enzymes were expressed in P. chrysosporium during primary metabolic growth under the control of the glyceraldehyde-3-phosphate dehydrogenase gene promoter, puri...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990943c
更新日期:1999-08-31 00:00:00
abstract::Hybridization to RNA is important for many applications, including antisense therapeutics, RNA interference, and microarray screening. Similar thermodynamic stabilities of A-U and G-U base pairs result in difficulties in selective binding to RNA. Moreover, A-U pairs are weaker than G-C pairs so that binding is sometim...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi901506f
更新日期:2009-11-24 00:00:00
abstract::The E-domain of staphylococcal protein A is one of five homologous IgG-binding domains designated E, D, A, B, and C that comprise the extracellular portion of protein A. The E-domain binds tightly to Fc fragments of IgG and binds certain Fv fragments with micromolar affinity. To explore further the structural features...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi961409x
更新日期:1996-12-03 00:00:00
abstract::The WSXWS motif is a highly conserved structural feature of the type I cytokine receptor family. It has previously been demonstrated that mutations in the (232)WSAWS(236) motif in the erythropoietin receptor (EPOR) can result in strongly inhibited surface expression, due to defective intracellular transport [Hilton, D...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034112p
更新日期:2003-07-22 00:00:00
abstract::The functional diversity of small GTP-binding proteins (G proteins) and their ability to function as molecular switches are based on their interactions with many different proteins. A wealth of structural data has revealed that their partners are often unrelated to each other in sequence and structure, but their bindi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049630u
更新日期:2004-06-08 00:00:00
abstract::A bifunctional molecule was genetically engineered which contained an amino-terminal effector domain that bound immunoglobulin Fc (fragment B of staphylococcal protein A) and a carboxyl-terminal domain that bound digoxin [a single-chain Fv (sFv)]. Effector and sFv binding properties were virtually identical with those...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00487a005
更新日期:1990-09-04 00:00:00
abstract::A novel liposomal method permits studies of Ca movements across the bilayers of multilamellar vesicles (MLV) which had entrapped the Ca-dependent, fluorescent indicator dye Fura 2. Ionomycin-mediated Ca translocation across MLV of phosphatidylcholine (PC)/dicetyl phosphate (DCP), 9:1, obeyed simple first-order kinetic...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00415a040
更新日期:1988-07-26 00:00:00
abstract::Aspartate-beta-semialdehyde dehydrogenase (ASADH) lies at the first branch point in the biosynthetic pathway through which bacteria, fungi, and the higher plants synthesize amino acids, including lysine and methionine and the cell wall component diaminopimelate from aspartate. Blocks in this biosynthetic pathway, whic...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi015713o
更新日期:2001-12-04 00:00:00
abstract::Periodate-oxidized tRNA(Phe) (tRNA(oxPhe)) behaves as a specific affinity label of tetrameric Escherichia coli phenylalanyl-tRNA synthetase (PheRS). Reaction of the alpha 2 beta 2 enzyme with tRNA(oxPhe) results in the loss of tRNAPhe aminoacylation activity with covalent attachment of 2 mol of tRNA dialdehyde/mol of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00391a033
更新日期:1987-08-25 00:00:00
abstract::Trifluoperazine (TFP) was shown to interact with the cyanogen bromide fragment 9 (CB9) (residues 84-135) of rabbit skeletal troponin C and with a synthetic peptide representing the N-terminal region of CB9. The phenothiazine did not affect the calcium binding property of CB9 as observed by proton magnetic resonance an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00276a010
更新日期:1983-03-29 00:00:00
abstract::Chemoenzymatic glycan remodeling by endoglycosidase-catalyzed deglycosylation and reglycosylation is emerging as an attractive approach for producing homogeneous glycoforms of antibodies, and the success of this approach depends on the discovery of efficient endoglycosidases and their glycosynthase mutants. We report ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00719
更新日期:2018-09-04 00:00:00
abstract::Formation of protein-protein assemblies is essential in maintaining cell structure and function. Conservation of structural motifs and binding sites is the result of evolutionary pressure for solutions compatible with both molecular economy and regulation. PDZ domains are a typical example: A conserved fold governs sp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi061869i
更新日期:2007-01-30 00:00:00
abstract::Anastellin is a small recombinant fragment derived from the extracellular matrix protein fibronectin; it comprises the first type III (FN3) domain without the two N-terminal β-strands. It inhibits angiogenesis, tumor growth, and metastasis in mouse models and requires endogenous fibronectin for its in vivo anti-angiog...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.7b00633
更新日期:2017-09-05 00:00:00
abstract::In eukaryotic cells, structures called heterochromatin play critical roles in nuclear processes ranging from gene repression to chromosome segregation. Biochemical and in vivo studies over the past several decades have implied that the diverse functions of heterochromatin rely on the ability of these structures to spr...
journal_title:Biochemistry
pub_type: 杂志文章,评审
doi:10.1021/acs.biochem.8b00401
更新日期:2018-05-01 00:00:00
abstract::Phosphoinositide 3-kinase gamma (PI3Kgamma) is activated by Gbetagamma release after stimulation of Galpha i -coupled receptors, involving a recruitment of the enzyme to the plasma membrane via interaction of the regulatory subunit p101 or p87 with Gbetagamma. The receptor-mediated release of Gbetagamma was, however, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi800596b
更新日期:2008-10-28 00:00:00
abstract::The first committed step of fatty acid and polyketides biosynthesis, the biotin-dependent carboxylation of an acyl-CoA, is catalyzed by acyl-CoA carboxylases (ACCases) such as acetyl-CoA carboxylase (ACC) and propionyl-CoA carboxylase (PCC). ACC and PCC in Streptomyces coelicolor are homologue multisubunit complexes t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi1005305
更新日期:2010-08-31 00:00:00
abstract::The membrane interaction properties of two single-residue variants, R6W and L5S, of the 17-amino acid neuropeptide dynorphin A (DynA) were studied by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Corresponding gene mutations have recently been discovered in humans and causatively linked to...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi4004205
更新日期:2013-06-18 00:00:00
abstract::The thermotropic behavior of aqueous dispersions of palmitoylsphingomyelin-cholesterol and lignoceryl-sphingomyelin-cholesterol mixtures has been examined by high-sensitivity differential scanning calorimetry. When less than 25 mol % cholesterol is mixed with either sphingomyelin, the calorimetric endotherm is compose...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00577a042
更新日期:1979-05-15 00:00:00
abstract::The Caenorhabditis elegans Werner syndrome protein, WRN-1, a member of the RecQ helicase family, has a 3'-5' DNA helicase activity. Worms with defective wrn-1 exhibit premature aging phenotypes and an increased level of genome instability. In response to DNA damage, WRN-1 participates in the initial stages of checkpoi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200791p
更新日期:2012-02-21 00:00:00
abstract::Type II dihydrofolate reductases (DHFRs) encoded by the R67 and R388 plasmids are different both in sequence and in structure from known chromosomal DHFRs. These plasmid-derived DHFRs are responsible for conferring trimethoprim resistance to the host strain. A derivative of R388 DHFR, RBG200, has been cloned and overp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00494a011
更新日期:1990-10-23 00:00:00
abstract::The binding of Ca2+ and the resulting change in catalytic specificity that allows phosphorylation of the calcium ATPase of sarcoplasmic reticulum by ATP were examined by measuring the amount of phosphoenzyme formation from [32P]ATP, or 45Ca incorporation into vesicles, after the simultaneous addition of ATP and EGTA a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00423a018
更新日期:1988-11-15 00:00:00
abstract::The characterization of cod somatolactin (SL), a new pituitary protein belonging to the growth hormone/prolactin family, is described. Cod SL has a molecular weight of 26 kDa and consists of 209 amino acids, of which eight are Cys. The protein has three disulfide bonds between residues Cys5-Cys15, Cys65-Cys181, and Cy...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00220a010
更新日期:1991-02-12 00:00:00
abstract::To understand the stabilization, folding, and functional mechanisms of proteins, it is very important to understand the structural and thermodynamic properties of the molten globule state. In this study, the global structure of the acid molten globule state, which we call MG1, of horse cytochrome c at low pH and high ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101806b
更新日期:2011-04-19 00:00:00
abstract::Argonaute (AGO) proteins play central roles in nucleic acid-guided interference that regulates gene expression and defend against foreign genetic elements in all life. Although much progress has been made with respect to the function of argonaute proteins in target recognition and cleavage, the detailed mechanism of t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00213
更新日期:2018-04-17 00:00:00