Abstract:
:The conformations of melittin, an amphipathic polypeptide consisting of 26 amino acid residues, and its hydrophobic (residues 1--19) and hydrophilic (residues 20--26) fragments were examined in various solvent systems, including H2O, 2H2O, 2-chloroethanol, and 1,2-dimyristoylphosphatidylcholine (DMPC) multilayers, by infrared spectroscopy. Water and 2-chloroethanol were used as reference solvents for characterizing the amide I and II vibrational frequencies of the polypeptide in systems reflecting unordered, beta-structure, or alpha-helical forms. In DMPC bilayer assemblies both melittin and its hydrophobic fragment F1 exhibit alpha-helical conformations. In contrast, infrared spectra for the hydrophilic F2 fragment are suggestive of a beta conformation with perhaps spectral contributions from random-coil configurations. The alpha-helical conformation of intact melittin in DMPC multilayer dispersions remains unchanged as the bilayer passes from the gel to liquid-crystalline state. For melittin-water solutions the infrared spectra monitor changes in population of specific conformations as the temperature is varied. Thus, for melittin concentrations in which tetramers are dominant high temperatures (31 degrees C) favor the alpha-helical form, while low temperatures (8 degrees C) lead to populations of both beta and alpha-helical structures. At lower melittin concentrations for which monomers persist, high temperatures favor an unordered polypeptide form, while low temperatures induce an alpha-helical conformation. Although peak-height intensity ratios AII/AI for the amide I and II regions are difficult to interpret rigorously, values of this parameter for aqueous solutions of melittin suggest a sensitivity to structural changes involving the aggregation properties of the polypeptide.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Lavialle F,Adams RG,Levin IWdoi
10.1021/bi00539a006subject
Has Abstractpub_date
1982-05-11 00:00:00pages
2305-12issue
10eissn
0006-2960issn
1520-4995journal_volume
21pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::Vibrational frequencies associated with FeC and CO stretching and FeCO bending modes have been determined via resonance Raman (RR) and infrared (IR) spectroscopy for cytochrome c peroxidase (CCP) mutants prepared by site-directed mutagenesis. These include the bacterial "wild type", CCP(MI), and mutations involving gr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00415a015
更新日期:1988-07-26 00:00:00
abstract::Thermodynamics of 39 oligonucleotides with internal G.T mismatches dissolved in 1 M NaCl were determined from UV absorbance versus temperature profiles. These data were combined with literature values of six sequences to derive parameters for 10 linearly independent trimer and tetramer sequences with G.T mismatches an...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962590c
更新日期:1997-08-26 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::Terminase enzymes are responsible for "packaging" of viral DNA into a preformed procapsid. Bacteriophage lambda terminase is composed of two subunits, gpA and gpNu1, in a gpA(1).gpNu1(2) holoenzyme complex. The larger gpA subunit is responsible for preparation of viral DNA for packaging, and is central to the packagin...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi050333e
更新日期:2005-07-19 00:00:00
abstract::When the identity of the metal ion activator, M, is changed within the series, Zn2+, Co2+, Mg2+, Ni2+, Mn2+, and Cd2+, the equilibrium distribution among the central complexes in the phosphoglucomutase system is markedly altered. (The central complexes are Ep-M-Glc-6-P, ED-M-Glc-1,6-P2, and Ep-M-Glc-1-P, where Ep and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00663a016
更新日期:1976-09-07 00:00:00
abstract::The present paper reports a study on the equilibria and kinetics of the acid-alkaline transition and the azide binding reaction by ferric Aplysia myoglobin. A single completely reversible spectrophotometric titration curve is found over the pH range from similar to 5 to similar to 9, with an apparent pK equals to 7.5 ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00679a006
更新日期:1975-04-22 00:00:00
abstract::We have analyzed by band-shift assays HeLa cell protein-DNA interactions on a stable cruciform DNA molecule. The stable cruciform was formed by heteroduplexing the HindIII-SphI fragment of SV40 virus DNA that contains the origin of replication with a derivative mutant containing a heterologous substitution at the cent...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00251a030
更新日期:1994-11-29 00:00:00
abstract::With the aid of high time resolution kinetic data extracted from a flow cytometer, we determined that there are two N-formyl peptide receptor states for human neutrophils at 4 degrees C: a low affinity and a high affinity state. Competitive binding of FMLP, FNLP, and t-BOC with FNLPNTL-FL revealed different kinetic ra...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi961088p
更新日期:1996-10-08 00:00:00
abstract::8-OxoGua (8-oxo-7,8-dihydroguanine) is produced in nucleic acids as well as in nucleotide pools of cells, by reactive oxygen species normally formed during cellular metabolic processes. MutT protein of Escherichia coli specifically degrades 8-oxoGua-containing deoxyribo- and ribonucleoside triphosphates to correspondi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi047550k
更新日期:2005-05-03 00:00:00
abstract::Glycogen synthase kinase 3β (GSK-3β) is a serine-threonine kinase belonging to the CMGC family that plays a key role in many biological processes, such as glucose metabolism, cell cycle regulation, and proliferation. Like most protein kinases, GSK-3β is regulated via multiple pathways and sites. We performed all-atom ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi100822q
更新日期:2010-12-28 00:00:00
abstract::To investigate the effect of a reduced level of selenocysteine (Sec) tRNA[Ser]Sec in selenoprotein biosynthesis, two mouse embryonic stem (ES) cell lines heterozygous for the corresponding gene were generated by homologous recombination of the host genome with targeting vectors encoding a deleted or a disrupted tRNA[S...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970608t
更新日期:1997-07-15 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::The extent of nativeness of the stable conformation of the thermolysin fragment containing the carboxyl-terminal third of the protein (from residues 206 to 316, denoted fragment FII) was examined by its immunogenic and antigenic characteristics. Antisera elicited in rabbits by either intact thermolysin or fragment FII...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00538a007
更新日期:1982-04-27 00:00:00
abstract::Ferredoxin I from Desulfovibrio africanus (Da FdI) is a small acidic [4Fe-4S] cluster protein that exchanges electrons with pyruvate-ferredoxin oxidoreductase (PFOR), a key enzyme in the energy metabolism of anaerobes. The thermodynamic properties and the electron transfer between PFOR and either native or mutated FdI...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0485878
更新日期:2004-12-14 00:00:00
abstract::Since a major function of RNA polymerase must be to bring together substrates in the optimal configuration for internucleotide bond formation, studies have been undertaken to understand the geometrical relationship of the two substrates. A model has been constructed for the geometry of interaction of two ATP molecules...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00477a017
更新日期:1990-06-26 00:00:00
abstract::The mammalian HIRA/UBN1/CABIN1/ASF1a (HUCA) histone chaperone complex deposits the histone H3 variant H3.3 into chromatin and is linked to gene activation, repression, and chromatin assembly in diverse cell contexts. We recently reported that a short N-terminal fragment of UBN1 containing amino acids 1-175 is necessar...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300050b
更新日期:2012-03-27 00:00:00
abstract::Peripheral benzodiazepine receptors (PBR), first described more than 20 years ago, have been attributed with many putative functions including ones in cellular proliferation and cellular respiration. Hence, it is quite conceivable that deregulation of this receptor could lead to pathology. We and others have reported ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi030251v
更新日期:2004-09-28 00:00:00
abstract::Eicosanoids have been implicated in the regulation of arterial smooth muscle cell (SMC) cholesteryl ester (CE) metabolism. These eicosanoids, which include prostacyclin (PGI2), stimulate CE hydrolytic activities. High-density lipoproteins (HDL), which promote cholesterol efflux, also stimulate PGI2 production, suggest...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00459a033
更新日期:1990-02-20 00:00:00
abstract::When rabbits are fed a diet supplemented with cholesterol, their plasma cholesterol levels increase markedly, and they develop atherosclerosis. Most of the plasma cholesterol exists as cholesteryl esters in very low density lipoproteins (VLDL) and intermediate-density lipoproteins (IDL). The triglyceride content of th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00268a025
更新日期:1982-12-07 00:00:00
abstract::Serine palmitoyltransferase (EC 2.3.1.50) catalyzes the condensation of L-serine and palmitoyl-CoA to yield 3-ketosphinganine in the first unique reaction of long-chain (sphingoid) base biosynthesis. The kinetic effects of changing the extracellular concentrations of the precursors for this pathway were studied with L...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00401a051
更新日期:1988-01-12 00:00:00
abstract::Indolotryptoline natural products represent a small family of structurally unique chromopyrrolic acid-derived antiproliferative agents. Like many prospective anticancer agents before them, the exploration of their potential clinical utility has been hindered by the limited information known about their mechanism of ac...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi501078j
更新日期:2014-11-18 00:00:00
abstract::The initial step in the l-kynurenine pathway is oxidation of l-tryptophan to N-formylkynurenine and is catalyzed by one of two heme enzymes, tryptophan 2,3-dioxygenase (TDO) or indoleamine 2,3-dioxygenase (IDO). Here, we address the role of the conserved active site Ser167 residue in human IDO (S167A and S167H variant...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi702405a
更新日期:2008-04-22 00:00:00
abstract::Porcine aortic myosin is a smooth muscle contractile protein similar to its striated muscle counterpart. Electrophoresis in sodium dodecyl sulfate indicates that the molecule consists of three classes of subunits with polypeptide chain molecular weights of 192,000, 19,000, and 15,000. At 277 nm the absorption spectrum...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00576a003
更新日期:1979-05-01 00:00:00
abstract::The heme-regulated inhibitor (HRI) of protein synthesis becomes activated in rabbit reticulocyte lysates in response to a variety of conditions including heme-deficiency, addition of oxidants, and heat shock. Activated HRI inhibits translation by catalyzing the phosphorylation of the alpha-subunit of eukaryotic initia...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00080a001
更新日期:1993-07-27 00:00:00
abstract::The neutron structure of subtilisin BPN' has been refined and analyzed at 2.0-A resolution. The structure studied was a mutant variant of subtilisin, Met222----Gln, and was used because large, uninhibited crystals could be grown, which was not the case for the native molecule. Comparison of the structure with that of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00219a008
更新日期:1991-02-05 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::It has previously been shown that mammalian RNA-peptidyl complexes are found in close association with tRNA, but can be separated from the bulk of the tRNA by benzoylated diethylaminoethylcellulose chromatography (Kull, F.J., and Soodak, M. (1971), Biochim. Biophys. Acta 246, l; Gadski, R.A., and Kull, F.J. (1973), Bi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00663a023
更新日期:1976-09-07 00:00:00
abstract::Cytochrome oxidase proteoliposomes were prepared from bovine heart oxidase. Size distributions determined by quasi-elastic light scattering (QELS) showed that there was a small population of large vesicles (120-200-nm diameter) and a large population of small vesicles (50-100-nm diameter). Trapping cytochrome c inside...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00468a010
更新日期:1990-04-24 00:00:00
abstract::Isopentenyl phosphate kinase (IPK) catalyzes the phosphorylation of isopentenyl phosphate to form the isoprenoid precursor isopentenyl diphosphate in the archaeal mevalonate pathway. This enzyme is highly homologous to fosfomycin kinase (FomA), an antibiotic resistance enzyme found in a few strains of Streptomyces and...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi201662k
更新日期:2012-01-31 00:00:00
abstract::Isothermal titration calorimetry (ITC) measurements of the binding 1-beta carbohydrate-substituted galactopyranoside derivatives to galectin-1 from bovine spleen, a dimer with one binding site per subunit, were performed at 283-285 and 298 K. The disaccharides were lactose, methyl beta-lactoside, lactulose, 4-O-beta-D...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9716478
更新日期:1998-04-28 00:00:00