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Terminal End (terminal + end)
Selected AbstractsPeptide based vaccine design: Synthesis and immunological characterization of branched polypeptide conjugates comprising the 276,284 immunodominant epitope of HSV-1 glycoprotein DJOURNAL OF PEPTIDE SCIENCE, Issue 3 2002Gábor Mez Abstract The importance of the length and conjugation site of a protective epitope peptide (276SALLEDPVG284) from glycoprotein D of herpes simplex virus in branched polypeptide conjugates has been investigated. A new set of peptides, with a single attachment site and truncated sequences, was prepared. The immunogenicity of conjugates and the specificity of antibody responses elicited were investigated in BALB/c, C57/Bl/6 and CBA mice. It was found that the covalent coupling of the peptide comprising the 276,284 sequence of gD through its Asp residue at position 281 did not influence the immunogenic properties of the epitope, while involvement of the side chain of Glu at position 280 almost completely abolished immunogenicity. These results clearly indicated that the conjugation site of the epitope peptide influenced the intensity and specificity of antibody responses. Comparison of the immunological properties of conjugates containing truncated gD peptides revealed the presence of two epitopes within the 276,284 region. One of the proposed epitopes is situated at the N -terminal (276,281) region, while the other is located at the C -terminal end of the sequence (279,284). Binding data demonstrated that some of the peptides comprising these epitopes induced gD-specific responses in their conjugated form and also elicited an immune response that conferred protection against lethal HSV-1 infection. The correlation of peptide- and gD-specific antibody responses with the protective effect of the immune response is discussed. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd. [source] Conformation of N-terminal HIV-1 tat (fragment 1,9) peptide by NMR and MD simulationsJOURNAL OF PEPTIDE SCIENCE, Issue 11 2001Meena Kanyalkar Abstract The N -terminal portion of HIV-1 Tat covering residues 1,9 is a competitive inhibitor of dipeptidyl peptidase IV (DP IV). We have used 1H NMR techniques, coupled with molecular dynamics methods, to determine the conformation of this peptide in the three diverse media: DMSO-d6, water (pH 2.7) and 40% HFA solution. The results indicate that in both DMSO-d6 and HFA the peptide has a tendency to acquire a type I ,-turn around the segment Asp5 -Pro6 -Asn7 -Ile8. The N -terminal end is seen to be as a random coil. In water, the structure is best described as a left-handed polyproline type II (PPII) helix for the mid segment region Asp2 to Pro6. The structures obtained in this study have been compared with an earlier report on Tat (1,9). Copyright © 2000 European Peptide Society and John Wiley & Sons, Ltd. [source] Purification and characterization of an endopeptidase that has an important role in the carboxyl terminal processing of antihypertensive peptides in Lactobacillus helveticus CM4LETTERS IN APPLIED MICROBIOLOGY, Issue 4 2004K. Ueno Abstract Aims:, To purify and characterize a peptidase that can catalyse C-terminal processing of antihypertensive peptide from Lactobacillus helveticus CM4. Methods and Results:, An endopeptidase which seems to process the carboxyl terminal end of two antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, was purified from Lactobacillus helveticus CM4 by four stages of column chromatography, using synthetic pro-peptide as a substrate. The molecular weight of the purified enzyme was estimated to be 67 000 by SEPHACRYL S-200 and 70 000 by SDS-PAGE analysis. The purified enzyme generated: (i) Val-Pro-Pro from Val-Pro-Pro-Phe-Leu and Val-Pro-Pro-Phe-Leu-Gln-Pro, and (ii) Ile-Pro-Pro from Ile-Pro-Pro-Leu-Thr and Ile-Pro-Pro-Leu-Thr-Gln-Thr, but theses peptides could not be generated from Val-Pro-Pro-Phe, Val-Pro-Pro-Phe-Leu-Gln, Ile-Pro-Pro-Leu and Ile-Pro-Pro-Leu-Thr-Gln. Part of the amino terminal sequence of the purified enzyme had homology to a previously reported pepO gene product. Conclusion:, These results suggest that the purified endopeptidase isolated in this study have an important role in the carboxyl terminal processing of two antihypertensive peptides in Lact. helveticus CM4. [source] Transition of nuclear proteins and chromatin structure in spermiogenesis of Sepia officinalis,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2007F. MartÍnez-Soler Abstract During spermiogenesis of Sepia officinalis histones are directly substituted by a molecule of precursor protamine, which is later transformed into the protamine through a deletion of the amino terminal end. In the present work, it is shown that the pattern of spermiogenic chromatin condensation consists of a phase of "patterning" and a phase of "condensation." In the phase of patterning, three structural remodelings are produced in the chromatin structure: [somatic-like chromatin,,,18 nm granules,,,25 nm fibers,,,44 nm fibers]. The first remodeling of the chromatin into granules of 18 nm takes place without the entrance of specific proteins in the spermiogenic nuclei. The second remodeling [granules of 18 nm,,,fibers of 25 nm] is due to the entrance of the precursor protamine and its interaction with the DNA,histone complex. The third remodeling [fibers of 25 nm,,,fibers of 44 nm] occurs simultaneously with the disappearance of histones from the chromatin. In the phase of condensation, the fibers of 44 nm coalesce among themselves to form progressively larger aggregates of chromatin. In this phase there are no substantial variations in the nuclear proteins, so that the condensation of the chromatin must respond to posttranscriptional changes of the precursor protamine (dephosphorylation, deletion of the amino-terminal end). Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Synthesis of 2-Fluoro N10 -Substituted Acridones and Their Cytotoxicity Studies in Sensitive and Resistant Cancer Cell Lines and Their DNA Intercalation StudiesARCHIV DER PHARMAZIE, Issue 11 2009Yergeri C. Mayur Abstract A series of 2-fluoro N10 -substituted acridone derivatives with varying alkyl side chain length with propyl, butyl substitution, and a tertiary amine group at the terminal end of the alkyl side chain were synthesized and screened against cancer cell lines SW 1573, SW 1573 2R 160 (P-gp substrate) which are non-small lung cancer cell lines, MCF-7, MCF-7/MR (BCRP substrate) are breast cancer cell lines, 2008 WT, 2008MRP1, 2008MRP2, 2008MRP3 are ovarian cancer cell lines, and human embryo kidney cell lines like HEK293, HEK293 MRP4, and HEK293 MRP5i. The propyl-series compounds showed lipophilicity in the range of 1.93 to 4.40 and the butyl series in the range of 2.37 to 4.78. The compounds 4, 7, and 8 showed good cytotoxicity against the 60 human cancer cell line panel of the National Cancer Institute, USA. The compounds 14 and 15 showed a better cytotoxicity in most of the cancer cell lines compared to other compounds tested. The DNA-binding properties of the compounds were evaluated based on their affinity or intercalation with CT-DNA measured with absorption titration. The compound 11 bearing planar tricyclic ring linked with a butyl methylpiperazino side chain showed the highest binding affinity with a binding constant (Ki) of 10.38×10 M,1. Evaluation of the compounds in cell lines with an overexpression of various multidrug resistance-related protein (MRP), P-glycoprotein (P-gp), or Breast Cancer Resistance Protein (BCRP) showed that all compounds are not substrates for any of these transporters. [source] Orthogonally Self-Assembled Multifunctional Block CopolymersCHEMISTRY - A EUROPEAN JOURNAL, Issue 44 2009Ashootosh Abstract We report the synthesis of telechelic poly(norbornene) and poly(cyclooctene) homopolymers by ring-opening metathesis polymerization (ROMP) and their subsequent functionalization and block copolymer formation based on noncovalent interactions. Whereas all the poly(norbornene)s contain either a metal complex or a hydrogen-bonding moiety along the polymer side-chains, together with a single hydrogen-bonding-based molecular recognition moiety at one terminal end of the polymer chain. These homopolymers allow for the formation of side-chain-functionalized AB and ABA block copolymers through self-assembly. The orthogonal natures of all side- and main-chain self-assembly events were demonstrated by 1H,NMR spectroscopy and isothermal titration calorimetry. The resulting fully functionalized block copolymers are the first copolymers combining both side- and main-chain self-assembly, thereby providing a high degree of control over copolymer functionalization and architecture and bringing synthetic materials one step closer to the dynamic self-assembly structures found in nature. [source] Proteome analysis of the thermoreceptive pit membrane of the western diamondback rattlesnake Crotalus atroxPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2003Hans Zischka Abstract Rattlesnakes detect their prey's temperature by means of a cavern-like structure, the pit organ. The sensory component of this organ lies within a thin membrane called the pit membrane. Proteome analysis conducted on this neurosensory tissue revealed only a relatively small number of proteins, thereby depicting its high degree of specialization. In addition to containing blood serum and structural proteins, the proteome of this membrane appears to be strikingly similar to that of isolated rattlesnake brain mitochondria. Indeed, our results show that over 80% of the detected tissue proteins are of mitochondrial origin. Fluorescence microscopy studies of these organelles indicate their dense arrangement and accumulation in structures which have been previously reported to be the terminal ends of free nerve fibers of the innervating trigeminal branches. Thus, original ultrastructural observations are paralleled by our findings at the molecular level. [source] Cyclopolymerization and Copolymerization of Functionalized 1,6-Heptadienes Catalyzed by Pd Complexes: Mechanism and Application to Physical-Gel FormationCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2010Sehoon Park Dr. Abstract Cationic Pd complexes, prepared from [PdCl(ArNC12H6NAr)(Me)] and Na[B{3,5(CF3)2C6H3}4] (NaBARF), catalyze the cyclopolymerization of 4,4-disubstituted 1,6-heptadienes. The polymers produced contain a trans -fused five-membered ring in each repeating unit. NMR spectroscopy and FAB mass spectrometry of the polymers formed indicated that the initiation end of the chain contains either the cyclopentyl group derived from the preformed Pd,monomer complex or a hydrogen atom left on the Pd center by the chain-transfer reaction. The stable cyclopentylpalladium species are involved in both initiation and propagation steps and undergo isomerization into (cyclopentylmethyl)palladium species followed by the insertion of a CHCH2 bond of a new monomer molecule into the PdCH2 bond. Copolymerization of 1,6-heptadiene derivatives with ethylene, catalyzed by the Pd complexes, yields polymers that contain trans five-membered rings and branched oligoethylene units. Copolymerization of isopropylidene diallylmalonate with 1-hexene affords a polymer with 26,% diene incorporation. The copolymerization consumes 1-hexene more readily than isopropylidene diallylmalonate, although gel permeation chromatography and NMR spectroscopy of the polymers produced show the formation of copolymers rather than of a mixture of homopolymers. Polymerization of 1-hexene initiated with a Pd,barbiturate complex and terminated with 5-allyl-5-hexylpyrimidine-2,4,6(1H,3H,5H)-trione/Et3SiH leads to polyhexene with barbiturate moieties at both terminal ends. Addition of 5-hexyl-2,4,6-triaminopyrimidine to a toluene solution of the telechelic poly(1-hexene) converts the solution into gel. [source] | |||||||||||||