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Peptide Bound (peptide + bound)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Disparate peptide-dependent thymic selection outcomes in ,2M-deficient mice versus TAP-1-deficient mice: implications for repertoire formation

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2003
Tetsuro Sasada
Abstract Fetal thymic organ cultures of N15-transgenic RAG-2,/, H-2b mice on normal, ,-2 microglobulin (,2M),/, or transporter associated with antigen processing (TAP-1),/, MHCI-deficient backgrounds were used to examine differentiation of thymocytes bearing a TCR specific for a viral peptide bound to H-2Kb. Strong agonists mediate negative selection in all mice whereas weak agonists are positively selecting in ,2M,/, mice but negatively selecting on TAP-1,/, or normal backgrounds. Very weak agonists and very weak antagonists are generally without effect in ,2M,/, mice yet foster differentiation in TAP-1,/, animals. The 20,40-fold reduction in ,2M,/, thymic H-2Kb surface expression suggests that the avidity of the TCR for peptide,MHCI accounts for these differences, consistent with effects of TCR density and individual thymic-peptide abundance in peptide,MHC complexes. TCR,self-MHC interaction dominates Kb -based selection, subtly modulated by peptides as revealed by X-ray crystallography. [source]

Development of an immuno tandem mass spectrometry (iMALDI) assay for EGFR diagnosis

PROTEOMICS - CLINICAL APPLICATIONS, Issue 12 2007
Jian Jiang
Abstract The epidermal growth factor receptor (EGFR) is highly expressed in a variety of tumors, and is therefore an important biomarker for cancer diagnosis and a target for cancer therapy. We have developed a novel peptide-based immuno tandem mass spectrometry (iMALDI) diagnostic assay for highly sensitive, highly specific, and quantitative analysis of EGFR, which we have applied to the detection of the EGFR peptide in three cell lines and in a tumor biopsy sample. This assay is capable of detecting the EGFR target peptide bound to the antibody beads at attomole levels. The ability to directly obtain amino acid sequence data by MS/MS on any affinity-captured peptides provides specificity to this diagnostic technique. This avoids the problem of "false positives" which can result from the nonspecific binding that can occur with any affinity-based technique. The addition of stable-labeled versions of the target peptide (synthesized from stable-isotope coded amino acids) as internal standards allows absolute quantitation of the target protein. [source]

REVIEW ARTICLE: Tolerance Mechanisms in Pregnancy: A Reappraisal of the Role of Class I Paternal MHC Antigens,

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2010
David A. Clark
Citation Clark DA, Chaouat G, Wong K, Gorczynski RM, Kinsky R. Tolerance mechanisms in pregnancy: a reappraisal of the role of class I paternal MHC antigens. Am J Reprod Immunol 2010; 63: 93,103 Problem, Allogeneic pregnancies have a survival advantage over syngeneic pregnancies, and paternal Class I MHC antigens have been implicated. In humans, HLA-C and HLA-G and E are expressed by subpopulations of fetal trophoblast. In mice, Qa-2, a Class Ib antigen, and classical H-2K antigens have been described. However, the mechanism of prevention of embryo demise in utero has not been critically assessed, and a number of conflicting ideas have not been addressed. The ,, T-cell receptor recognizes peptide bound to the groove in Class I MHC, and peptides have profound effects on the interaction of KIR receptors on T and NK cells with Class I MHC. Methods, Data on prevention of pregnancy loss (abortion) in poly IC-treated mice were reviewed along with information about prevention of losses in the abortion-prone CBA × DBA/2 model. This information was combined with data on paternal antigen expression at different times in pregnancy when key events determining outcome are thought to transpire, and role of tolerance signaling molecules such as CD200. Current data on models supporting a role for ,true' uterine NK cells (TuNKs) versus blood NK cells in the uterus (BuNKs) and role of MHC,KIR interaction were reviewed along with incompatible data in the literature. Results, Whilst paternal Class I MHC appears important, there is an important role for paternal non-MHC minor antigens (small peptides) that bind to the antigen-presenting groove of Class I MHC. BuNKs along with CD8+ T cells and Treg cells appear more important than TuNKs where the role of the latter appears primarily to promote angiogenesis. When during pregnancy the maternal immune system cells are first exposed to paternal Class I + peptide is uncertain, but at the time of implantation, if not earlier, seems likely. Conclusion, Suppression of pregnancy loss by paternal/embryo Class I MHC depends on the presence of paternal peptides. This greatly complicates existing models of Class I,KIR interactions in feto-maternal tolerance or rejection. It is important to consider all the data when devising explanatory models. [source]

Fusarium oxysporum trypsin at atomic resolution at 100 and 283,K: a study of ligand binding

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2001
Wojciech R. Rypniewski
The X-ray structure of F. oxysporum trypsin has been determined at atomic resolution, revealing electron density in the binding site which was interpreted as a peptide bound in the sites S1, S2 and S3. The structure, which was initially determined at 1.07,Å resolution and 283,K, has an Arg in the S1 specificity pocket. The study was extended to 0.81,Å resolution at 100,K using crystals soaked in Arg, Lys and Gln to study in greater detail the binding at the S1 site. The electron density in the binding site was compared between the different structures and analysed in terms of partially occupied and overlapping components of peptide, solvent water and possibly other chemical moieties. Arg-soaked crystals reveal a density more detailed but similar to the original structure, with the Arg side chain visible in the S1 pocket and residual peptide density in the S2 and S3 sites. The density in the active site is complex and not fully interpreted. Lys at high concentrations displaces Arg in the S1 pocket, while some main-chain density remains in sites S2 and S3. Gln has been shown not to bind. The free peptide in the S1,S3 sites binds in a similar way to the binding loop of BPTI or the inhibitory domain of the Alzheimer's ,-protein precursor, with some differences in the S1 site. [source]