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Chimeric Peptide (chimeric + peptide)
Selected Abstracts, -Peptide Conjugates: Syntheses and CD and NMR Investigations of ,/, -Chimeric Peptides, of a DPA- , -Decapeptide, and of a PEGylated , -HeptapeptideHELVETICA CHIMICA ACTA, Issue 12 2009James Gardiner Abstract ,3 -Peptides consisting of six, seven, and ten homologated proteinogenic amino acid residues have been attached to an , -heptapeptide (all d- amino acid residues; 4), to a hexaethylene glycol chain (PEGylation; 5c), and to dipicolinic acid (DPA derivative 6), respectively. The conjugation of the , -peptides with the second component was carried out through the N-termini in all three cases. According to NMR analysis (CD3OH solutions), the (M)- 314 -helical structure of the , -peptidic segments was unscathed in all three chimeric compounds (Figs.,2, 4, and 5). The , -peptidic section of the ,/, -peptide was unstructured, and so was the oligoethylene glycol chain in the PEGylated compound. Thus, neither does the appendage influence the , -peptidic secondary structure, nor does the latter cause any order in the attached oligomers to be observed by this method of analysis. A similar conclusion may be drawn from CD spectra (Figs.,1, 3, and 5). These results bode well for the development of delivery systems involving , -peptides. [source] The hinge region fragment of immunoglobulin G improves immunogenicity of recombinant gonadotrophin-releasing hormone conjugated to the T-helper epitope in designing peptide vaccinesIMMUNOLOGY, Issue 1pt2 2009Jinshu Xu Summary In our previous study, the hinge fragment (225,232/225,,232,) of human immunoglobulin G1 (IgG1) was used as a space peptide linker for synthesizing the GnRH3,hinge,MVP chimeric peptide, whereby three repeated gonadotrophin-releasing hormone (GnRH) units and a T-cell epitope from measles virus fusion protein (MVP) were amide-bond-linked at the N and C terminus, respectively, to the hinge peptide for producing anti-GnRH antibody responses. To investigate whether or not the hinge region fragment can improve the immunogenicity of GnRH, we further synthesized and purified GnRH3,hinge,MVP, GnRH3,hinge and GnRH3,MVP using recombinant DNA technology. Under high pH conditions, GnRH3,hinge,MVP was capable of forming double-chain structures. Immunization of male mice with the immunogens of GnRH3,hinge,MVP resulted in the generation of high-titre antibodies specific for GnRH. The synthetic GnRH3,hinge and GnRH3,MVP induced a lower titre of anti-GnRH antibody than GnRH3,hinge,MVP. This was followed by a decrease in serum testosterone levels, which resulted in a low level of expression of the relaxin-like factor gene in the testis. Our data suggest that peptide and T-cell epitopes oriented at the N-terminus or C-terminus of hinge peptides simplify the antigenic peptide conjugates and may be considered as potential synthetic immunogens. [source] Correlations between synthetic peptide-based enzyme immunoassays and immunofluorescence assay for detection of human herpesvirus 8 antibodies in different Argentine populationsJOURNAL OF MEDICAL VIROLOGY, Issue 6 2006Celeste Pérez Abstract Human herpesvirus 8 (HHV-8) antibody tests vary in sensitivity and specificity, depending on the population tested and on the type of assay. In this study, we evaluated the sensitivity and specificity of two peptide enzyme immunoassays using a multiple antigenic peptide (PK8.1-MAP) or a chimeric peptide (PK8.1-orf65) as the antigens and determined the HHV-8 seroprevalence in different Argentine polulations using an immunofluorescence assay (IFA) as reference. For analysis, when either or both of the peptide EIAs were positive, the specimen was considered positive (PEIA). We estimated the sensitivity and specificity of PEIA to be 97% using Kaposi's sarcoma (KS) patients and healthy individuals as positive and negative controls respectively. Then, we expanded the control groups to include IFA positive men who have sex with men (MSM) and IFA negative blood donors. The sensitivity decreased to 83% but specificity remained high at 98%. Concordance between PEIA and IFA was 77% for 1/40 IFA titers and increased to 90% for titers ,1/160. Seroprevalences for HHV-8 performed in the HIV positive MSM were (IFA 73.1%; PEIA55.2%); heterosexuals (52.5%, 22.2%), which includes injecting drug users (IDU) (54.0%, 32.4%) and non-IDU (51.6%, 16.1%). The inclusion of non-KS HHV-8 IFA positive individuals to the positive controls may be a substantial improvement towards the realistic assessment of assay sensitivity. These peptide EIAs can be used for trends in populations with high probablity of being HHV-8 infected and negative results should be confirmed by IFA. IFA test is still the most suitable test for populations with low probabilities of being infected. J. Med. Virol. 78:806,813, 2006. © 2006 Wiley-Liss, Inc. [source] Side chain contributions to the interconversion of the topological isomers of guanylin-like peptidesJOURNAL OF PEPTIDE SCIENCE, Issue 6 2005Dr Axel Schulz Abstract The peptide hormones guanylin and uroguanylin are ligands of the intestinal guanylyl cyclase-C (GC-C) that is involved in the regulation of epithelial water and electrolyte transport. The small peptides contain 15 and 16 amino acids, respectively, and two disulfide bonds with a 1,3/2,4 connectivity. This structural feature causes the unique existence of two topological isoforms for each peptide in an approximate 3:2 ratio, with only one of the isoforms exhibiting GC-C-activating potential. The two uroguanylin isomers can be separated by HPLC and are of sufficient stability to be studied separately at ambient temperatures while the two guanylin isomers are rapidly interconverting even at low temperatures. Both isomers show clearly distinguishable 1H chemical shifts. To investigate the influence of certain amino acid side chains on this isomerism and interconversion kinetics, derivatives of guanylin and uroguanylin (L -alanine scan and chimeric peptides) were designed and synthesized by Fmoc solid-phase chemistry and compared by HPLC and 2D 1H NMR spectroscopy. Amino acid residues with the most significant effects on the interconversion kinetics were predominantly identified in the COOH-terminal part of both peptides, whereas amino acids in the central part of the peptides only moderately affected the interconversion. Thus, the conformational conversion among the isomers of both peptides is under the control of a COOH-terminal sterical hindrance, providing a detailed model for this dynamic isomerism. Our results demonstrate that kinetic control of the interconversion process can be achieved by the introduction of side chains with a defined sterical profile at suitable sequence positions. This is of potential impact for the future development of GC-C peptide agonists and antagonists. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd. [source] | ||||||||||