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Peptide Motif (peptide + motif)

Distribution by Scientific Domains

Medical Sciences	45%
Chemistry	18%

Selected Abstracts

Functionalized, Swellable Hydrogel Layers as a Platform for Cell Studies

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2009
Núria Marí-Buyé
Abstract This paper reports the design, synthesis and characterization of thin films as a platform for studying the separate influences of physical and chemical cues of a matrix on the adhesion, growth and final phenotype of cells. Independent control of the physical and chemical properties of functionalized, swellable hydrogel thin films is achieved using initiated chemical vapor deposition (iCVD). The systematic variation in crosslink density is demonstrated to control the swelling ability of the iCVD hydrogel films based on 2-hydroxyethyl methacrylate (HEMA). At the same time, the incorporation of controllable concentrations of the active ester pentafluorophenyl methacrylate (PFM) allows easy immobilization of aminated bioactive motifs, such as bioactive peptides. Initial cell culture results with human umbilical vein endothelial cells (HUVEC) indicate that the strategy of using PFM to immobilize a cell-adhesion peptide motif onto the hydrogel layers promotes proper HUVEC growth and enhances their phenotype. [source]

Identification of SPARC as a candidate target antigen for immunotherapy of various cancers

INTERNATIONAL JOURNAL OF CANCER, Issue 6 2010
Mitsuhiro Inoue
Abstract To establish efficient anticancer immunotherary, it is important to identify tumor-associated antigens (TAAs) directing the immune system to attack cancer. A genome-wide cDNA microarray analysis identified that secreted protein acidic and rich in cysteine (SPARC) gene is overexpressed in the gastric, pancreatic and colorectal cancer tissues but not in their noncancerous counterparts. This study attempted to identify HLA-A24 (A*2402)-restricted and SPARC-derived CTL epitopes. We previously identified H-2Kd -restricted and SPARC-derived CTL epitope peptides in BALB/c mice, of which H-2Kd -binding peptide motif is comparable with that of HLA-A24 binding peptides. By using these peptides, we tried to induce HLA-A24 (A*2402)-restricted and SPARC-reactive human CTLs and demonstrated an antitumor immune response. The SPARC-A24-1143,151 (DYIGPCKYI) and SPARC-A24-4225,234 (MYIFPVHWQF) peptides-reactive CTLs were successfully induced from peripheral blood mononuclear cells by in vitro stimulation with these two peptides in HLA-A24 (A*2402) positive healthy donors and cancer patients, and these CTLs exhibited cytotoxicity specific to cancer cells expressing both SPARC and HLA-A24 (A*2402). Furthermore, the adoptive transfer of the SPARC-specific CTLs could inhibit the tumor growth in nonobese diabetic/severe combined immunodeficient mice bearing human cancer cells expressing both HLA-A24 (A*2402) and SPARC. These findings suggest that SPARC is a potentially useful target candidate for cancer immunotherapy. [source]

Monoclonal and polyclonal humoral immune response to EC HER-2/NEU peptides with low similarity to the host's proteome

INTERNATIONAL JOURNAL OF CANCER, Issue 5 2002
Abraham Mittelman
Abstract We are studying peptide immunogenicity as a function of the similarity level to the host's proteome. By using as a model the breast/prostate cancer-associated HER-2/neu antigen, we analyzed the monoclonal and polyclonal humoral immune responses against HER-2/neu peptide motifs not shared with the host proteome. We show here that (i) a mouse monoclonal antibody (MAb) raised against the extracellular domain (EC) of human HER-2/neu oncoprotein recognized a linear peptide motif endowed with low similarity level to the mouse proteome; (ii) likewise, human sera from breast/prostate cancer patients preferentially recognized peptide fragments from the EC of the HER-2/neu oncoprotein having sequences that are not present in the human proteome. Together with previous results obtained in other disease models (cervical cancer-associated HPV16 E7 oncoprotein and Pemphigus vulgaris auto-antigen desmoglein-3), the present data suggest that a low level of sequence similarity to the host's proteome might be an important factor in shaping the pool of B cell epitopes. © 2002 Wiley-Liss, Inc. [source]

ASARM-truncated MEPE and AC-100 enhance osteogenesis by promoting osteoprogenitor adhesion

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 9 2008
Andrew P. Sprowson
Abstract Matrix extracellular phosphoglycoprotein (MEPE) is a member of the SIBLING (Small Integrin-Binding Ligand, N-linked Glycoprotein) family of secreted glycophosphoproteins. Several previous studies have demonstrated that MEPE and its peptide motif, AC-100, may regulate bone mass and influence osteoblast activity, suggesting its potential for inclusion in novel therapeutic strategies aimed at increasing osteogenesis. Our study uses in vitro approaches to assess how adhesion of nonadherent cells is influenced by MEPE and whether response to MEPE is dependent on the maturity of osteoblastic cells. Truncated MEPE (ASARM removed) or AC-100 enhanced the adhesion, spreading, and focal complex formation of unadhered osteoblastic cells leading to increased differentiation and bone formation after 28 days of culture. Furthermore, addition of truncated MEPE or AC-100 to mature osteoblasts had no significant effect on bone formation. Our data supports an action for truncated MEPE and AC-100 in altering the physiology of immature poorly adherent cells which subsequently influences the way in which these cells interact with a substrate to facilitate their survival and/or commitment to the osteoblast lineage. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1256,1262, 2008 [source]

The Evolution of the Endozepine-like Peptide (ELP) in the Mammalian Testis

REPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2001
R Ivell
The endozepine-like peptide (ELP) is a testis-specific isoform of the acyl-CoA binding protein (ACBP) and shares the latter's peptide motif for binding mid-long chain acyl-CoA groups. ELP is expressed both as mRNA and protein at high levels in the testes of a wide range of mammals, including rodents, carnivores and ruminants. However, the ELP gene is progressively inactivated through primate evolution, with no protein detectable in a range of primates studied, including human. In nonprimate species, ELP is expressed in very late postmeiotic germ cell stages only, such that its function in these species is probably associated with the metabolism of the mature spermatozoon. Current research is looking at both the function of the ELP protein and the haploid regulation of the gene. [source]

Molecular characteristics of an immobilization antigen gene of the fish-parasitic protozoan Ichthyophthirius multifiliis strain ARS-6

AQUACULTURE RESEARCH, Issue 16 2009
De-Hai Xu
Abstract Ichthyophthirius multifiliis (Ich), a ciliated protozoan parasite of fish, expresses surface antigens (i-antigens), which react with host antibodies that render them immobile. The nucleotide sequence of an i-antigen gene of I. multifiliis strain ARS-6 was deduced. The predicted protein of 47 493 Da is comprised of 460 amino acids (aa's) arranged into five imperfect repeats with periodic cysteine residues with the structure: CX(19)20CX2CX16,27CX2CX20(21)CX3. The N-terminal aa's typify a signal peptide motif while a stretch of C-terminal aa's resemble a glycosyl,phosphatidyl,inositol (GPI)-anchor addition site. The degree of deduced i-antigen aa sequence identity of strain ARS-6 (GenBank accession # ACH87654 and # ACH95659) with other I. multifiliis i-antigen sequences present in GenBank ranges from 99% to 36% identity with 52 kDa i-antigens of I. multifiliis strain G5 (accession #s AAK94941 and AAK01661 respectively). Immunoblot analysis of i-antigens following exposure of I. multifiliis theronts to catfish anti- I. multifiliis immune serum did not show any appreciable alteration in i-antigen expression. The mechanism that regulates i-antigen expression in I. multifiliis remains a puzzling question. [source]

A Novel Heavy-Atom Label for Side-Specific Peptide Iodination: Synthesis, Membrane Incorporation and X-ray Reflectivity

CHEMPHYSCHEM, Issue 9-10 2009
Philipp E. Schneggenburger
Abstract A novel iodine peptide label for X-ray analysis of membrane-active peptide structures is applied to solid-phase peptide synthesis. The resulting pore-structured labeled peptide as well as a non-labeled reference were reconstituted in lipid bilayer stacks (see scheme). The results indicate the exhibition of a membrane-spanning ,5.6 -double helical peptide structure and illustrate the quality of the new label. Structural parameters, such as conformation, orientation and penetration depth of membrane-bound peptides and proteins that may function as channels, pores or biocatalysts, are of persistent interest and have to be probed in the native fluid state of a membrane. X-ray scattering in combination with heavy-atom labeling is a powerful and highly appropriate method to reveal the position of a certain amino acid residue within a lipid bilayer with respect to the membrane normal axis up to a resolution of several Ångstrøm. Herein, we report the synthesis of a new iodine-labeled amino acid building block. This building block is intended for peptide incorporation to provide high intensities for electron density difference analysis of X-ray reflectivity data and improve the labeling potential for the lipid bilayer head-group and water region. The novel building block as well as the commercially available non-iodinated analogue, required for X-ray scattering, was implemented in a transmembrane peptide motif via manual solid-phase peptide synthesis (SPPS) following the fluorenylmethyloxycarbonyl (Fmoc)-strategy. The derived peptides were reconstituted in lipid vesicles as well as in highly aligned multilamellar lipid stacks and investigated via circular dichroism (CD) and X-ray reflectivity. Thereby, it has been revealed that the bulky iodine probe neither causes conformational change of the peptide structure nor lamellar disordering of the membrane complexes. [source]

Controlling Affinity Binding with Peptide-Functionalized Poly(ethylene glycol) Hydrogels

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2009
Chien-Chi Lin
Abstract Poly(ethylene glycol) (PEG) hydrogels functionalized with peptide moieties have been widely used in regenerative medicine applications. While many studies have suggested the importance of affinity binding within PEG hydrogels, the relationships between the structures of the peptide motifs and their binding to protein therapeutics remain largely unexplored, especially in the recently developed thiol-acrylate photopolymerization systems. Herein, Förster resonance energy transfer (FRET) and thiol-acrylate photopolymerizations are employed to investigate how the architectures of affinity peptides in crosslinked hydrogels affect their binding to diffusible proteins. The binding between diffusible streptavidin and biotinylated peptide immobilized to PEG hydrogel network was used as a model system to reveal the interplay between affinity binding and peptide sequences/architectures. In addition, peptides with different structures are designed to enhance affinity binding within PEG hydrogels and to provide tunable affinity-based controlled delivery of basic fibroblast growth factor (bFGF). This study demonstrates the importance of affinity binding in controlling the availability of hydrogel-encapsulated proteins and provides strategies for enhancing affinity binding of protein therapeutics to bound peptide moieties in thiol-acrylate photopolymerized PEG hydrogels. The results presented herein should be useful to the design and fabrication of hydrogels that retain and exhibit sustained release of growth factors for promoting tissue regeneration. [source]

Monoclonal and polyclonal humoral immune response to EC HER-2/NEU peptides with low similarity to the host's proteome

Identification of the peptide motifs that interact with HLA-DR8 (DRB1*0802) in Streptococcus mutans proteins

MOLECULAR ORAL MICROBIOLOGY, Issue 4 2002
Y. Nomura
A glucosyltransferase (GTF) and a surface protein antigen (PAc) of Streptococcus mutans have been suggested as possible components of an effective dental caries vaccine. To identify antigenic peptides in GTF and PAc that bind to MHC class II (HLA-DR8, DRB1*0802) molecules, we investigated binding activities to DR8 molecules of overlapping synthetic peptides at several sites in GTF and in the alanine-rich repeating region of PAc using an ELISA-inhibition competitive binding assay for the interaction between the HLA-DR molecule and the PAc (316,334) peptide. Six GTF peptides and 10 PAc peptides strongly bound to the HLA-DR8 molecule. In a homology analysis of the amino acid sequences of the six GTF peptides, two binding motifs were found in L/Y, ,Y/L,A/N and Y/L, ,N/G/E, ,Y,V/L/P. Moreover, a new binding motif in PAc was found in L- ,Y-A. It is suggested that these binding motifs could be useful in designing a dental caries vaccine in humans. [source]

Structural Diversity of PDZ,Lipid Interactions

CHEMBIOCHEM, Issue 4 2010
Rodrigo Gallardo
Abstract PDZ domains are globular protein modules that are over-and-above appreciated for their interaction with short peptide motifs found in the cytosolic tail of membrane receptors, channels, and adhesion molecules. These domains predominate in scaffold molecules that control the assembly and the location of large signaling complexes. Studies have now emerged showing that PDZ domains can also interact with membrane lipids, and in particular with phosphoinositides. Phosphoinositides control various aspects of cell signaling, vesicular trafficking, and cytoskeleton remodeling. When investigated, lipid binding appears to be extremely relevant for PDZ protein functionality. Studies point to more than one mechanism for PDZ domains to associate with lipids. Few studies have been focused on the structural basis of PDZ,phosphoinositide interactions, and the biological consequences of such interactions. Using the current knowledge on syntenin-1, syntenin-2, PTP-Bas, PAR-3 and PICK1, we recapitulate our understanding of the structural and biochemical aspects of PDZ,lipid interactions and the consequences for peptide interactions. [source]