Abstract:
:A study of the dynamics and mechanism of the various thermotropic phase transitions undergone by the hydrated monoacylglycerides monoolein and monoelaidin, in the temperature range of 20-120 degrees C and from 0 to 5 M NaCl, has been undertaken. Measurements were made by using time-resolved X-ray diffraction at the Cornell High-Energy Synchrotron Source. The lamellar chain order/disorder, lamellar/cubic (body centered, space group No. 8), cubic (body centered, No. 8)/cubic (primitive, No. 4), cubic (body centered, No. 12)/cubic (primitive, No. 4), cubic (primitive, No. 4)/fluid isotropic, cubic (body centered, No. 12)/inverted hexagonal, cubic (primitive, No. 4)/inverted hexagonal, and hexagonal/fluid isotropic transitions were examined under active heating and passive cooling by using a jump in temperature to effect phase transformation. All of the transitions with the exception of the cubic (body centered, No. 8)/cubic (primitive, No. 4) and the cubic (body centered, No. 12)/cubic (primitive, No. 4) cooling transitions were found (1) to be repeatable, (2) to be reversible, and (3) to have an upper bound on the transit time (time required to complete the transition) of less than or equal to 3 s. The shortest transit times recorded for the various phase changes in the heating direction were less than or equal to 1.9 (lamellar chain melting), less than or equal to 1.7 [lamellar liquid crystal/cubic (body (body centered, No. 8)], less than or equal to 0.5 [cubic (body centered, No. 8)/cubic (primitive, No. 4)], less than or equal to 0.9 [cubic (primitive, No. 4)/hexagonal], less than or equal to 1.3 [cubic (body centered, No. 12)/cubic (primitive, No. 4) and cubic (body centered, No. 12)/hexagonal], and less than or equal to 0.6 s (hexagonal/fluid isotropic). For the exceptions noted above, the transitions were slow with transit times ranging from 0.5 to 30 min and displayed pronounced hysteresis and/or undercooling. Regardless of the direction of the transitions, all but one appear to be two state to within the sensitivity limits of the time-resolved method. In the case of the lamellar liquid crystal/cubic (body centered, No. 8) transition a stable intermediate of unknown identity was apparent. In addition to the time-resolved measurements, data were obtained on the stability of the various phases in the temperature range of 20-120 degrees C and from 0 to 5 M NaCl. In the case of fully hydrated monoolein, high salt strongly favors the hexagonal over the cubic (body centered, No. 8) phase and slightly elevates the hexagonal/fluid isotropic transition temperature.(ABSTRACT TRUNCATED AT 400 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Caffrey Mdoi
10.1021/bi00394a008subject
Has Abstractpub_date
1987-10-06 00:00:00pages
6349-63issue
20eissn
0006-2960issn
1520-4995journal_volume
26pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC) are both thiamin diphosphate-dependent enzymes. The two share a common three-dimensional structure and catalyze a similar chemical reaction, i.e., decarboxylation of 2-keto acids. However, they vary significantly in their substrate utilization patter...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9008402
更新日期:2009-09-08 00:00:00
abstract::Previous studies have demonstrated that lung-specific proteins are associated with surfactant lipids, particularly the highly surface active subfraction known as tubular myelin. We have isolated a surfactant-associated protein complex with molecular weight components of 36 000, 32 000, and 28 000 and reassembled it wi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00322a026
更新日期:1985-01-01 00:00:00
abstract::A new Escherichia coli RNA polymerase mutant was isolated which exhibited reduced accuracy of chain elongation in vivo and in vitro. The novel isolation procedure consisted of simultaneous selection for rifampicin resistance and screening for increased leakiness of an early, strongly polar nonsense mutation of lacZ, o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00368a013
更新日期:1986-10-07 00:00:00
abstract::The ionic and nucleotide requirements for the in vitro polymerization of microtubules from purified brain tubulin have been characterized by viscometry. Protein was purified by successive cycles of a temperature dependent assembly-diassembly scheme. Maximal polymerization occurred at a concentration of 0.1 M Pipes (pi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a032
更新日期:1975-07-01 00:00:00
abstract::Antifreeze proteins lower the freezing point of their solution by binding to ice and inhibiting its growth. One of several structurally different antifreeze proteins in fishes (type II) is homologous to the carbohydrate-recognition domain of Ca2+-dependent lectins and adopts the same three-dimensional fold. Type II an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9820513
更新日期:1998-12-22 00:00:00
abstract::Whereas the salt-dependent conformational transition of acid-denatured horse ferricytochrome c at pH 2 is approximated by a two-state mechanism from the acid-unfolded state to the molten globule state [Kataoka, M., Hagihara, Y., Mihara, K., & Goto, Y. (1993) J. Mol. Biol. 229, 591-596], the corresponding transition in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00095a017
更新日期:1993-11-09 00:00:00
abstract::Oxidation of low-density lipoprotein (LDL), the major cholesterol carrier in plasma, is thought to promote atherogenesis via several mechanisms. One proposed mechanism involves fusion of oxidized LDL in the arterial wall; another involves oxidation-induced amyloid formation by LDL apolipoprotein B. To test these mecha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700225a
更新日期:2007-05-15 00:00:00
abstract::Thermal and chemical modification of protein structures is known to affect their interfacial activity. We have looked in detail at the effect of heating on the structure and subsequently the surface properties of LTP1, a nonspecific lipid transfer protein from barley, both in the presence and in the absence of its lip...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi901328f
更新日期:2009-12-29 00:00:00
abstract::Murine epidermal growth factor (EGF), a 53 amino acid protein, has been modified by enzymic digestion, site-specific chemical reactions, and recombinant DNA technology. After trypsin digestion the EGF derivatives EGF1-48 (called EGF-T) and EGF1-45 (called EGF-T2) were separated from the residual EGF and the C-terminal...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00414a005
更新日期:1988-07-12 00:00:00
abstract::Attenuated total reflection Fourier transform infrared (ATR-FTIR) difference spectroscopy has been performed on samples of bovine cytochrome c oxidase that have been deposited as a thin film on the surface of a silicon microprism. The technique has several advantages over transmission methods in terms of amount of mat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0109717
更新日期:2002-01-22 00:00:00
abstract::DNA-dependent synthesis of beta-galactosidase was optimized in extracts made from cells lysed by a standard French pressure cell. Extracts made at 3200 psi synthesized up to 25-fold more beta-galactosidase than extracts made at 7500 psi. beta-Galactosidase synthesis was cyclic 3', 5' AMP dependent, as expected, and in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00624a016
更新日期:1977-03-08 00:00:00
abstract::The selective reaction of SH containing proteins and peptides with NTCB (2-nitro-5-thiocyanobenzoic acid) has been reported (Degani, Y., & Patchornick, A. (1974) Biochemistry 13, 1; Jacobson, G.A., Schaffer, M.H., Stark, G.R., & Vanaman, T.C. (1973) J. Biol. Chem. 248, 6583). With this reagent, cysteinyl peptide bonds...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00618a022
更新日期:1978-12-12 00:00:00
abstract::The Staphylococcus aureus sortase transpeptidase SrtA isoform is responsible for the covalent attachment of virulence and colonization-associated proteins to the bacterial peptidoglycan. SrtA utilizes two substrates, undecaprenol-pyrophosphoryl-MurNAc(GlcNAc)-Ala-D-isoGlu-Lys(epsilon-Gly(5))-D-Ala-D-Ala (branched Lipi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035920j
更新日期:2004-02-17 00:00:00
abstract::The PLL(PTE-like lactonase)-group of enzymes within the amidohydrolase superfamily hydrolyze N-acyl-homoserine lactones (AHLs) that are involved in bacterial quorum-sensing pathways. These enzymes possess the (beta/alpha)(8)-barrel fold and serve as attractive templates for in vitro evolution and engineering of quorum...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9004045
更新日期:2009-05-26 00:00:00
abstract::Dehydroquinate synthase has been purified 9000-fold from Escherichia coli K-12 (strain MM294). The synthase is encoded by the aroB gene, which is carried by plasmid pLC29-47 from the Carbon-Clarke library. Construction of an appropriate host bearing pLC29-47 results in a strain that produces 20 times more enzyme than ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00314a036
更新日期:1984-09-11 00:00:00
abstract::Numerous studies have been published stressing the importance of finding ligands that can bind specifically to DNA secondary structures. Several have identified ligands that are presented as having specific binding to the G-quadruplex; however, these were not originally tested on the complementary i-motif structure. T...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00968
更新日期:2019-01-29 00:00:00
abstract::Alkalimetric, spectrophotometric, NMR, and resonance Raman titrations are reported for the sulfonamide Neoprontosil in aqueous solution. An assignment of the magnetic resonance peaks for each of the Neoprontosil protons has been made. Neoprontosil is shown to have two "coupled" iity of the microscopic pKs for these tw...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00580a024
更新日期:1979-06-26 00:00:00
abstract::Phosphoenolthiopyruvate, the analogue of phosphoenolpyruvate in which the bridging oxygen of the phosphate ester is replaced by sulfur, has been synthesized from methyl acrylate and dimethyl (chlorothio)phosphonate. The compound is a substrate for alkaline phosphatase, pyruvate kinase, enolase, and phosphoenolpyruvate...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00404a038
更新日期:1988-02-23 00:00:00
abstract::The bovine protein tyrosine phosphatase (BPTP) is a member of the class of low-molecular weight protein tyrosine phosphatases (PTPases) found to be ubiquitous in mammalian cells. The catalytic site of BPTP contains a CX(5)R(S/T) phosphate-binding motif or P-loop (residues 12-19) which is the signature sequence for all...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990381x
更新日期:1999-09-07 00:00:00
abstract::Regulation of cellular processes by dietary nutrients is known to affect the likelihood of cancer development. One class of cancer-preventive nutrients, isothiocyanates (ITCs), derived from the consumption of cruciferous vegetables, is known to have various effects on cellular biochemistry. One target of ITCs is macro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi3005494
更新日期:2012-09-25 00:00:00
abstract::The membrane-active, cationic, β-hairpin peptide, arenicin, isolated from marine polychaeta Arenicola marina exhibits a broad spectrum of antimicrobial activity. The peptide in aqueous solution adopts the significantly twisted β-hairpin conformation without pronounced amphipathicity. To assess the mechanism of arenici...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi200746t
更新日期:2011-07-19 00:00:00
abstract::The interaction of insulin with its receptor is complex. Kinetic and equilibrium binding studies suggest coexistence of high- and low-affinity binding sites or negative cooperativity. These phenomena and high-affinity interactions are dependent on the dimeric structure of the receptor. Structure-function studies of in...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi801693h
更新日期:2008-12-02 00:00:00
abstract::The incorporation of extensively fluorinated, or fluorous, analogues of hydrophobic amino acids into proteins potentially provides the opportunity to modulate the physicochemical properties of proteins in a predictable manner. On the basis of the properties of small fluorocarbon molecules, extensively fluorinated prot...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi901481k
更新日期:2009-11-17 00:00:00
abstract::High signal-to-noise Fourier transform infrared (FTIR) spectra of the 5-hydroxytryptamine (serotonin) receptor (5-HT(3)R) and the nicotinic acetylcholine receptor (nAChR) were obtained by microscope FTIR spectroscopy using micrometer-sized, fully hydrated protein films. Because this novel procedure requires only nanog...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035113k
更新日期:2003-12-02 00:00:00
abstract::The interactions of 4-thiouridine and 5-[(methylamino)methyl]-2-thiouridine in tRNA and of phosphorothioate esters in nucleic acids with an organomercurial have been investigated. For this purpose, an affinity electrophoretic system has been developed in which the mercury derivative has been covalently immobilized in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00410a048
更新日期:1988-05-17 00:00:00
abstract::The structure and folding of a novel human insulin mutant, [Thr(B27) --> Pro, Pro(B28) --> Thr]insulin (PT insulin), in aqueous solution and in mixtures of water and 2,2,2-trifluoroethanol (TFE) have been studied by NMR spectroscopy. It was found that PT insulin has a highly flexible structure in pure water and is pre...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0108150
更新日期:2001-09-04 00:00:00
abstract::A complex derived from chromatin containing one molecule of each of histones H2A, H2B, H3, and H4, termed core protein, was studied by 13C and 1H nuclear magnetic resonance. 13C line widths, when analyzed and compared with those of native and thermally unfolded representative globular proteins, showed that regions of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00632a008
更新日期:1977-06-28 00:00:00
abstract::The solution structure and dynamics of human insulin are investigated by 2D 1H NMR spectroscopy in reference to a previously analyzed analogue, des-pentapeptide(B26-B30) insulin (DPI; Hua, Q.X., & Weiss, M.A. (1990) Biochemistry 29, 10545-10555). This spectroscopic comparison is of interest since (i) the structure of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00236a025
更新日期:1991-06-04 00:00:00
abstract::The Salmonella typhimurium leu-500 promoter is active only in topA strains. In an earlier study (Chen, D., Bowater, R., Dorman, C., & Lilley, D. M. J. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 8784-8788), we showed that the activity of this promoter on a circular plasmid is a function of the transcription and translati...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00211a027
更新日期:1993-12-07 00:00:00
abstract::A metabolite of vitamin D has been isolated in pure form from incubation of 25-hydroxyvitamin D3 with embryonic chick calvarial cells that had been grown on Cytodex 1 microcarrier beads. The isolation involved dichloromethane extraction of the cells and incubation medium, followed by Sephadex LH-20 column chromatograp...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00274a012
更新日期:1983-03-01 00:00:00