Peptide motifs of HLA-A1, -A11, -A31, and -A33 molecules.
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Amino Acid Sequence↗
Biomedical subjects
G Jung
Publications and source records attributed to G Jung.
Dominant aromatic/aliphatic C-terminal anchor in HLA-B*2702 and B*2705 peptide motifs.
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Amino Acid Sequence↗
Pool sequencing of natural HLA-DR, DQ, and DP ligands reveals detailed peptide motifs, constraints of processing, and general rules.
We have approached the problem of MHC class II ligand motifs by pool sequencing natural peptides eluted from HLA-DR, DQ, and DP molecules. The results indicate surprisingly clear patterns, although not quite as clear as with natural class I ligands. The most striking feature is a highly dominant Proline at position 2. We interpret this to be a consequence of aminopeptidase N-like activity in processing. Another general aspect is the existence of three to four hydrophobic or aromatic anchors, whereby the first and the last are separated by five to eight residues. The peptide motifs for HLA-DR1, DR5, DQ7, and DPw4 are allele-specific and differ by spacing and occupancy of anchors. The anchors tend to be flanked by clusters of charged residues, and small residues, especially Ala, are frequent in the motif centers. These detailed motifs allow one to interpret most previous (DR-) motifs as fitting one or more of the anchors or conserved clusters. The relative motif symmetry suggests the possibility of bidirectional binding of peptides in the class II groove.
Alleles↗
Peptide motifs of HLA-A3, -A24, and -B7 molecules as determined by pool sequencing.
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Amino Acid Sequence↗
Development of high-cell-density fermentation for heterologous interleukin 1 beta production in Kluyveromyces lactis controlled by the PHO5 promoter.
The use of a phosphate organic form taken up by Kluyveromyces lactis removes repression of the PHO5 promoter and releases heterologous interleukin 1 beta synthesis while providing sufficient phosphate for growth. The oxidative metabolism of high-cell-density fed-batch and chemostat cultures was thus maintained under derepressed protein synthesis conditions. Interleukin 1 beta production was then growth-associated, an unusual mode of protein synthesis regulation under the control of the PHO5 promoter.
6-Phytase↗
Effects of polycations on ion channels formed by neutral and negatively charged alamethicins.
The effects of the peptide polycations salmon protamine (M(r) = 4332, z = +21) and poly-L-lysine (M(r) approximately equal to 100,000, z approximately equal to +775) on ion channels formed by synthetic alamethicin Alm-F30 (one negative charge), natural Alm-F50 (neutral) and phosphorylated Alm-F50 (two negative charges) reconstituted in planar lipid bilayers have been studied at the single channel level. It was observed that both polycations in micromolar concentrations transiently block ion permeation through the channels formed by each alamethicin analogue, although in case of the neutral Alm-F50 to a significantly lesser extent. Poly-L-lysine showed to be more effective than protamine in blocking these channels. If either polycation is present in the cis-compartment, blockade occurs only at cis positive membrane voltages. At constant polycation concentration, dwell times in the blocked state increase when salt concentration is lowered, and decrease at acidic pH with an apparent pK of 4.8. Mean lifetime of blockade events shortens when membrane voltage is increased, which suggests that both polycations may permeate through the oligomeric alamethicin channels if conductance levels are > 2. We suggest that blockade is caused by electrostatic binding of a single polycation molecule to the C-terminal channel mouth; in case of Alm-F30, Glu18 has to be considered as the putative binding site. Our results provide further evidence for the barrel-stave model and a parallel orientation of dipole monomers in the channel aggregate, the C-termini facing the membrane side with the more positive membrane potential.
Action Potentials↗
A 16mer peptide of the human autoantigen calreticulin is a most prominent HLA-DR4Dw4-associated self-peptide.
The human Ca(2+)-binding (storage) protein calreticulin, located in the lumen of the endoplasmic reticulum, is proposed to play a role as autoantigen: anticalreticulin autoantibodies occur in the sera of patients with SLE and patients with onchocerciasis (calreticulin shows a high sequence homology to the Onchocerca volvulus antigen RAL-1). Here we present sequencing data of a HLA-DR4Dw4-associated calreticulin peptide fragment, Cal(295-310), purified from a DR4Dw4 self-peptide pool. Cal(295-310) proved to be one of three commonest self-peptides associated with DR4Dw4 molecules that were isolated from the EBV-transformed B-cell line BSM (DR4Dw4, DRw53). We tested the binding of Cal(295-309) and the analogous RAL-1 peptide to HLA-DR molecules: Cal(295-309) exhibited specific binding characteristics for DR4Dw4. Binding assays using self-peptide analogues with replaced amino acids led us to a DR4Dw4-binding motif with anchor residues at relative positions 1 and 6. The sequencing data suggest that calreticulin is a frequently processed intracellular protein. The abundance of calreticulin makes the presentation of different calreticulin peptides associated with HLA-D molecules likely to occur, supporting the immunologic relevance of this molecule.
Amino Acid Sequence↗
Lipopeptide-polyoxyethylene conjugates as mitogens and adjuvants.
Two lipopeptide analogues of the Escherichia coli lipoprotein rendered water-soluble by polyoxyethylene were tested for mitogenicity in vitro in murine and human B lymphocytes and for adjuvant activity in vivo in mice. These highly amphiphilic lipopeptides retained the biological activity other lipopeptides usually exerted which supports the hypothesis of specific interactions of lipopeptides with membranes of reactive cells. The activation of human B lymphocytes by these lipopeptides was much less pronounced compared to that of murine cells. However, given in combination with anti-CD40 antibodies plus interleukin-4, human B lymphocytes could synergistically be stimulated to proliferate. As an adjuvant, the polyoxyethylene linked lipopeptides were almost as potent as Freund's adjuvants and other basic lipopeptides. Being water-soluble, these novel analogues are easy to apply and they are suitable for field studies as adjuvants when sonication can not usually be provided.
Adjuvants, Immunologic↗
High-affinity analogues of neuropeptide Y containing conformationally restricted non-proteinogenic amino acids.
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Amino Acid Sequence↗
Intraperitoneal injection of synthetic bacterial lipopeptides does not cause a rise in circulating inflammatory cytokines.
The production of TNF-alpha, IL-1 and IL-6 was measured in mice after i.p. injections of the synthetic bacterial lipopeptide Pam3Cys-Ala-Gly, a potent macrophage and B cell activator in vitro. Only minor amounts of IL-6 and no TNF-alpha were detectable in the serum of mice injected with 10 or 100 micrograms of Pam3Cys-Ala-Gly. Lipopeptide concentrations up to 1000 micrograms failed to induce IL-1, and TNF-alpha production and serum IL-6 levels were only slightly elevated. In contrast to Pam3Cys-Ala-Gly, i.p. injections of LPS were accompanied by high levels of the inflammatory cytokines TNF-alpha, IL-1 and IL-6 suggesting fundamental differences of the mode of action of these two substances when applied in vivo.
Amino Acid Sequence↗
Colonic transit time in nonidiopathic Parkinson's syndrome.
Constipation is well known to be a frequent symptom in idiopathic Parkinson's disease. In this study, colonic transit time was measured in 16 patients with nonidiopathic Parkinson's syndrome (non-IPS). These patients all had lacunar infarcts in the caudate, putamen, or globus pallidus, as a cause of the disease, as demonstrated by MRI. In comparison with the control group there was only a slightly longer transit time with, on the whole, a normal transit time (about 59 h). In only five cases was the transit time significantly decreased. Our results suggest that colonic transit is only prolonged in patients with idiopathic PD, whereas it is normal in non-IPS. This seems to be cause by a multi-degenerative process in the idiopathic disease.
Aged↗
Mapping of antigenic and immunogenic sites of Haemophilus influenzae outer membrane protein P6 using synthetic lipopeptides.
The immune response to the P6 protein of Haemophilus influenzae was characterized with 24 synthetic icosapeptides and 45 dodecapeptides conjugated to the immune stimulator N-palmitoyl-S-[2,3-(bispalmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-( S)-serine . The antigenicity of these lipopeptides was investigated by enzyme-linked immunosorbent assays with rabbit anti-P6 serum. The epitopes of P6 protein were identified and localized within residues 31-46 and 59-70 and in the C-terminal part of the P6 protein. Mice were immunized with lipoicosapeptides without using additional adjuvants or carriers and the antibody titers were measured with isolated P6 protein and lipopeptides in a dot blot assay. Lipopeptides containing the sequence pattern QILDAHAA (P6 47-54) and the mouse B cell epitope GEYV (P6 43-46) induced high titers of anti P6 antibodies. These murine antibodies were able to neutralize the intact bacterium Haemophilus influenzae.
Amino Acid Sequence↗
Biological activity of the Escherichia coli lipoprotein: detection of novel lymphocyte activating peptide segments of the molecule and their conformational characterization.
The lipoprotein (LP) from Escherichia coli and other Enterobacteriaceae as well as lipoprotein derived lipopeptides constitute potent B lymphocyte mitogens. Several synthetic peptide segments of the lipoprotein were tested for mitogenic activity towards splenocytes of BALB/c mice. Mitogenic effects were observed for the lipoprotein fragments LP-(2-15), LP-(2-20), LP-(2-25), and LP-(33-47), and a less pronounced effect was determined for LP-(2-10). The mitogenicity of the peptides could be further enhanced by their attachment to the lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2R,S)-propyl]-(R)- cysteine (Pam3Cys). The additional insertion of 6-aminohexanoic acid (Ahx) between the peptide segments and Pam3Cys further increased mitogenicity. Thus, in addition to the known mitogenic N-terminal lipopeptide of lipoprotein, additional peptide segments of the molecule were shown to exhibit a biological activity.
Amino Acid Sequence↗
Pentapeptide identified as a monoclonal antibody binding site in the serine-protease domain of t-PA.
The first defined sequential epitope of the tissue plasminogen activator (t-PA) was determined by a monoclonal antibody against a synthetic peptide segment corresponding to peptide sequence 341-354 of t-PA. This segment was selected by computer assisted epitope prediction. Balb/c mice were immunized with catalase-peptide and tripalmitoyl-S-glyceryl-cys-teinyl-seryl-peptide conjugates. A monoclonal antibody derived from this immunization was reactive with native recombinant t-PA (rt-PA) and reduced carboxymethylated recombinant t-PA (RCM rt-PA). The sequential epitope was detected by Pepscan method using overlapping octa- and nonapeptides. By fine epitope mapping with tetra-, penta-, hexa- and heptapeptides the epitope was minimized to the pentapeptide EEEQK (347-351). Replacement set analysis confirmed the importance of this amino acid sequence, especially of the amino acid E348, for antibody binding. Functional assays of rt-PA were not affected by this antibody indicating that the epitope has no influence on the enzymatic center and the binding site of the inhibitor. The analysis demonstrates that the predicted recognition site of the monoclonal antibody 17-134/11 is exposed on the surface of the native rt-PA molecule.
Amino Acid Sequence↗
Analysis of a naturally occurring HLA class I-restricted viral epitope.
A previously described nonapeptide sequence motif for antigens recognized by T cells in the context of the human major histocompatibility complex (MHC) molecule HLA-A2.1 was used to identify the natural epitope of influenza A virus matrix protein. We show here that the peptide with the sequence GILGFVFTL is the synthetic analogue of the natural epitope by demonstrating the presence of the corresponding peptide on MHC molecules of virus-infected cells. The role of the hydrophobic anchor amino acids in positions 2 and 9, which constitute the epitope motif, was investigated with synthetic variants of the epitope and cytotoxic T lymphocytes as indicator cells. The crucial role of the side chains of amino acids in those positions was evidence by their influence on the efficiency of T-cell stimulation.
Amino Acid Sequence↗
Allele-specific peptide ligand motifs of HLA-C molecules.
The consensus motifs of HLA-Cw3, -Cw4, -Cw6, and -Cw7 ligands were determined by pool sequencing. Together with information obtained by sequencing of some prominent individual peptides, the results indicate the following: (i) all four HLA-C molecules are associated with peptides. (ii) These peptides adhere to allele-specific motifs that are similar to those of to HLA-A or -B molecules; they have a preferred length of nine amino acids and an anchor residue at the C terminus. (iii) All four HLA-C molecules analyzed exhibit related peptide motifs, although each allelic product shows individual characteristics in fine specificity. (iv) Processing and origin of peptides appear not to be different from that of other class I molecules. (v) No obvious difference at C-terminal position 9 was present in the peptides isolated from the two dimorphic variants of HLA-C that determine dominant resistance to natural killer NK1-specific cells (HLA-Cw4, -Cw6) or to NK2-specific cells (HLA-Cw3, -Cw7) and that differ in two residues in or near the pocket at position 9.
Amino Acid Sequence↗
Isolation and analysis of the rat genomic sequence encoding Cu/Zn superoxide dismutase.
A rat genomic DNA (SOD1) encoding Cu/Zn superoxide dismutase (SOD1) (superoxide; superoxide oxidoreductase, EC 1.15.1.1) was cloned and sequenced. The rat SOD1 gene consisted of five exons and four introns spanning about 6 kb. The transcription start point (tsp) was observed 93 bp upstream from the ATG codon by primer extension analysis. The 5'-flanking sequence of SOD1 contained two CCAAT box motifs, a TATA box and four GC-like boxes. In the 3'-flanking region of SOD1, a polyadenylation signal, consensus sequence YGTGTTYY, and a G/T cluster were observed. A rat identifier (ID) sequence, a repetitive element of the rat genome, was located at between 569 and 484 bp upstream from the tsp.
Amino Acid Sequence↗
Identification of Trk binding sites for SHC and phosphatidylinositol 3'-kinase and formation of a multimeric signaling complex.
Phosphotyrosine-containing synthetic peptides were used to identify the binding sites for cellular polypeptides involved in nerve growth factor receptor/Trk-mediated signal transduction. In vitro association of SHC and the p85 subunit of phosphatidylinositol 3'-kinase with the Trk tyrosine kinase was prevented only by phosphorylated Y-490- and Y-751-containing peptides, respectively. In spite of the close proximity of the p85 binding site to that of phospholipase C gamma (Y-785), both target proteins are able to interact with the same receptor molecule simultaneously.
Amino Acid Sequence↗