Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lys-His-Gly-NH2 has been claimed to selectively induce B cell precursors to differentiate into mature B lymphocytes. In the present study, the effects of this tripeptide and a control compound having the reverse sequence (Gly-His-Lys-NH2) on growth and differentiation of chicken and mouse B cell precursors were investigated. When chicken bone marrow (BM) cells from 15-day-old embryos were treated for 18 hr with either of the tripeptides, the frequency of Bu-1 antigen-bearing cells increased. Moreover, when embryonic bursa cells were stimulated in vitro with phorbol myristate acetate, which induces them to proliferate and undergo terminal differentiation into immunoglobulin (Ig)-secreting cells, these compounds caused a 10-fold increase in the number of Ig-secreting cells but did not increase cell proliferation. They had no effect on neonatal or adult bursa cells. Embryonic bursa cells were cultured in the presence of either of the tripeptides and metabolically labeled with [35S]methionine. When immunoprecipitated Ig was analyzed by two-dimensional gel electrophoresis, no differences in mu heavy or lambda light chain diversity patterns could be detected, indicating that neither of these compounds enhances Ig diversification. The effect of these tripeptides on murine B cell precursors was assayed in cultures of BM cells depleted of mature B cells by 5-fluorouracil. When precursor cells were incubated without adherent BM stromal cells, they did not respond to the tripeptides. However, after incubation of precursors with adherent stromal BM cells for 2 days, followed by treatment with either of the two tripeptides, differentiation into lipopolysaccharide-reactive mature B cells took place. Incubation of precursors with adherent stromal BM cells in the absence of tripeptides was not sufficient to allow the precursors to complete differentiation. In addition, both tripeptides acted synergistically with interleukin 1 or interleukin 3. In conclusion, these tripeptides seem to enhance precursor B cell differentiation in a lineage-nonspecific manner rather than to function as lineage-specific differentiation hormones.
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PMID:A role for Lys-His-Gly-NH2 in avian and murine B cell development. 278 13

The interaction between lipopolysaccharide (LPS) and an LPS-sensitive serine protease zymogen, factor C, purified from horseshoe crab (Tachypleus tridentatus) hemocytes, was investigated to elucidate the LPS-mediated activation of factor C. The rate of activation of the zymogen factor C was highly dependent on the concentration of LPS and on temperature, and the curve of amount of LPS versus activation showed saturation at 37 degrees C. Moreover, a high-molecular-mass complex formed between factor C and LPS was found in a gel-filtration experiment on a Sepharose 4B column. This complex formation was also confirmed by double diffusion analysis on agarose plates. Triton X-100, which destroys LPS micelles, strongly inhibited the LPS-mediated activation of factor C but not activated factor C. These results indicate that the binding of factor C with LPS is required for its activation and that only LPS-associated factor C generates the active factor C. On the other hand, the LPS-mediated activation of factor C was strongly inhibited by the S-alkylated heavy chain derived from factor C. In contrast, the S-alkylated factor C-light chain did not show any inhibitory effect on the activation of factor C, suggesting that the heavy chain located in the NH2-terminal portion of factor C contains an LPS-binding region.
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PMID:Interaction between lipopolysaccharide and intracellular serine protease zymogen, factor C, from horseshoe crab (Tachypleus tridentatus) hemocytes. 316 90

The horseshoe crab clotting factor, factor C, present in the hemocytes is a serine-protease zymogen activated with lipopolysaccharide. It is a two-chain glycoprotein (Mr = 123,000) composed of a heavy chain (Mr = 80,000) and a light chain (Mr = 43,000) [T. Nakamura et al. (1986) Eur. J. Biochem. 154, 511-521]. In our continued study of this zymogen, we have now also found a single-chain form of factor C (Mr = 123,000) in the hemocyte lysate. The heavy chain had the NH2-terminal sequence of Ser-Gly-Val-Asp-, consistent with that of the single-chain factor C, indicating that the heavy chain is derived from the NH2-terminal part of the molecule. The light chain had an NH2-terminal sequence of Ser-Ser-Gln-Pro-. Incubation of the two-chain zymogen with lipopolysaccharide resulted in the cleavage of a Phe-Ile bond between residues 72 and 73 of the light chain. Concomitant with this cleavage, the A (72 amino acid residues) and B chains derived from the light chain were formed. The complete amino acid sequence of the A chain was determined by automated Edman degradation. The A chain contained a typical segment which is similar in sequence to a family of repeats in human beta 2-glycoprotein I, complement factors B, protein H, C4b-binding protein, and coagulation factor XIII b subunit. The NH2-terminal sequence of the B chain was Ile-Trp-Asn-Gly-. This chain contained the serine-active site sequence-Asp-Ala-Cys-Ser-Gly-Asp-Ser-Gly-Gly-Pro-. These results indicate that horseshoe crab factor C exists in the hemocytes in a single-chain zymogen form and is converted to an active serine protease by hydrolysis of a specific Phe-Ile peptide bond.
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PMID:Lipopolysaccharide-sensitive serine-protease zymogen (factor C) of horseshoe crab hemocytes. Identification and alignment of proteolytic fragments produced during the activation show that it is a novel type of serine protease. 330 57

The complete amino acid sequence of anti-lipopolysaccharide (LPS) factor purified from the hemocytes lysate of the American horseshoe crab, Limulus polyphemus, was determined by characterization of the NH2-terminal sequence and the peptides generated after digestion of the protein with lysyl endopeptidase, clostripain, and Staphylococcus aureus V8 protease. Upon sequencing the peptides by the automated Edman method, the following primary structure was obtained: (Sequence: in text). During the sequence analysis, two species of the protein, which differed from each other at one locus, were found and characterized. L. polyphemus anti-LPS factor was a basic protein consisting of a single polypeptide chain of 101 residues and a calculated molecular weight of 11,786 or 11,800. The hydrophobic NH2-terminal sequence and the clustering of positive charges found in the disulfide loop yielded a typical amphipathic character of this protein. Moreover, L. polyphemus anti-LPS factor showed 83% sequence identity with the Tachypleus tridentatus protein, and the sequence similar to that observed in the EF-hand structure was found to contain in the COOH terminal portions of these proteins, although its function is unknown.
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PMID:Primary structure of anti-lipopolysaccharide factor from American horseshoe crab, Limulus polyphemus. 366 49

A potent anticoagulant, anti-lipopolysaccharide (LPS) factor, found in limulus hemocytes inhibits the LPS-mediated activation of limulus coagulation cascade and shows an antibacterial action against R-types of Gram-negative bacteria (Morita, T., Ohtsubo, S., Nakamura, T., Tanaka, S., Iwanaga, S., Ohashi, K., and Niwa, M. (1985) J. Biochem. (Tokyo) 97, 1611-1620). The complete amino acid sequence of this substance was determined by sequencing the peptides obtained by selective proteolytic cleavage. The NH2-terminal end of anti-LPS factor was pyroglutamic acid. Anti-LPS factor had two variant residues at position 36 and the COOH-terminal end, respectively. The following sequence was assigned to anti-LPS factor, and it was also confirmed by fast atom bombardment mass spectrometry. less than EGGIWTQLALALVKNLATLWQSGDFQFLGHE (formula; see text) Limulus anti-LPS factor consisted of a single chain of 102 residues with 2 half-cystines in disulfide linkage. Its NH2-terminal region up to 20 residues was highly hydrophobic, and positively charged residues were clustered mainly within the disulfide loop. By searching the homologous sequence in known protein sequences with that of anti-LPS factor, we found a structural homology between anti-LPS factor and alpha-lactalbumin/lysozyme family.
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PMID:Primary structure of limulus anticoagulant anti-lipopolysaccharide factor. 371 Oct 91

Exposure of limulus hemocytes to bacterial endotoxins (lipopolysaccharide, LPS) results in the activation of the intracellular clotting system, consisting of several protein components. During the separation of these components, a potent anticoagulant, named anti-LPS factor, which inhibits the endotoxin-mediated activation of the coagulation cascade, was found in hemocytes from both Tachypleus tridentatus and Limulus polyphemus (Tanaka, S., et al. (1982) Biochem. Biophys. Res. Commun. 105, 717-723). The principle isolated from the Tachypleus hemocyte lysate by column chromatographies on dextran sulfate-Sepharose CL-6B and Sephadex G-50 under sterile conditions was a simple basic protein with an apparent molecular weight of 15,000. It consisted of a single chain polypeptide containing a total of 128 amino acids. The COOH-terminal end was presumed to be histidine, but no NH2-terminal end reactive to phenylisothiocyanate was detected. The isolated anti-LPS factor specifically inhibited the endotoxin-mediated activation of factor C, which has recently been identified as an LPS-sensitive serine protease zymogen in the hemocytes. This inhibition appeared to be due to the binding of anti-LPS factor with LPS. Moreover, anti-LPS factor had an antibacterial effect on the growth of Gram-negative bacteria (Salmonella minnesota R595 and 1114W) but not on that of Gram-positive bacteria (Staphylococcus aureus 209P). These biological activities of the isolated anti-LPS factor suggest an important role in cellular defence of limulus against microbial invasion.
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PMID:Isolation and biological activities of limulus anticoagulant (anti-LPS factor) which interacts with lipopolysaccharide (LPS). 403 Jul 41

Flagellin proteins from several different strains of Pseudomonas pseudomallei have been isolated and purified to homogeneity by mechanical shearing and differential centrifugation techniques. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis yielded flagellin monomer protein bands with an estimated M(r) of 43,400. No lipopolysaccharide contamination of the purified protein preparations was detectable by silver staining of flagellin displayed on polyacrylamide gels and by Western immunoblotting with P. pseudomallei antilipopolysaccharide monoclonal antibody. NH2-terminal amino acid sequence analysis of the flagellin protein of P. pseudomallei 319a revealed significant homology with flagellins from Proteus mirabilis, Bordetella bronchiseptica, and Pseudomonas aeruginosa PAK. Rabbit polyclonal antiserum raised against the 319a flagellin protein reacted with 64 of 65 P. pseudomallei strains tested. The polyclonal antiserum proved effective in inhibiting the motility of these organisms in motility agar plates. Passive immunization studies demonstrated that 319a flagellin-specific antiserum was capable of protecting diabetic rats from challenge with a heterologous P. pseudomallei strain.
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PMID:Isolation and characterization of Pseudomonas pseudomallei flagellin proteins. 751 8

Lipopolysaccharide from Klebsiella pneumoniae O3, which possesses the mannose homopolysaccharide as the O-specific polysaccharide, exhibits an extraordinarily high ability to activate the human complement system. We isolated the mannose-binding protein with a Klebsiella O3 lipopolysaccharide affinity column. The protein isolated had a molecular mass of much higher than 200 kDa, and it consisted of subunits with an apparent molecular mass of 32 kDa. The NH2-terminal sequence of the 32-kDa subunits was completely consistent with a part of the amino acid sequence of human serum mannose-binding protein. In immunoblotting, an anti-mannose-binding protein monoclonal antibody was definitely reactive with the isolated protein with the higher molecular mass. The protein isolated was bound exclusively to lipopolysaccharides possessing the mannose homopolysaccharide, not to lipopolysaccharide possessing the heteropolysaccharides. Klebsiella O3 lipopolysaccharide did not exhibit a high anticomplement activity in the serum from which the mannose-binding protein was depleted. It was concluded that the serum factor that bound to Klebsiella O3 lipopolysaccharide may be mannose-binding protein and that it may play a crucial role in the strong complement activation by Klebsiella O3 lipopolysaccharide.
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PMID:Binding of mannose-binding protein to Klebsiella O3 lipopolysaccharide possessing the mannose homopolysaccharide as the O-specific polysaccharide and its relation to complement activation. 754 May 96

Administration of monoclonal anti-CD3 antibody to mice treated with Propionibacterium acnes induced secretion of a high level of gamma interferon (IFN-gamma) into the circulation system, while it induced no significant release in untreated mice. In order to analyze this high-level induction of IFN-gamma in these bacterium-treated mice, we investigated the factors that might be involved. An activity that induces IFN-gamma in T cells was observed in the liver extracts of mice treated with P. acnes and subsequently challenged with lipopolysaccharide. Here, we purified an IFN-gamma-inducing factor from the liver extract to homogeneity and characterized it. Its molecular mass was 18 to 19 kDa, and its pI was 4.9. The amino acid sequence of the NH2-terminal portion was determined and shown to have no similarities to any protein in the EMBL, GenBank, and PIR data bases. The same molecule was also demonstrated in the serum factor that was previously reported to have an IFN-gamma-inducing activity and to have an apparent molecular mass of 75 kDa. Moreover, the activity of this serum factor was recovered in the fraction containing the 18- to 19-kDa protein under reducing conditions and was shown to have the same NH2-terminal amino acid sequence as that of the factor from the liver extract. In addition to the ability to induce IFN-gamma, this protein augmented T-cell proliferation and NK activity in the spleen cells. Thus, several of its biological activities were apparently similar to those of interleukin-12. These results indicated that this novel protein, which exhibited marked costimulatory activity on IFN-gamma production in vitro, was elevated vivo in response to P. acnes treatment. This factor, probably released from the producing cells by lipopolysaccharide stimuli, may be involved in the high-level induction of IFN-gamma in the P. acnes-treated mice.
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PMID:A novel costimulatory factor for gamma interferon induction found in the livers of mice causes endotoxic shock. 755 6

Interleukin-1 beta (IL-1 beta)-converting enzyme (ICE) is a novel cysteine protease that cleaves the 31-kD inactive cytoplasmic IL-1 beta precursor into active extracellular 17-kD IL-1 beta. The ICE gene product is a 45-kD proenzyme that requires proteolytic processing to activate ICE. Active ICE is a heterodimer consisting of equal amounts of p20 and p10 subunits. Generation of active ICE is affected by the removal of an 11-kD NH2-terminal precursor domain (p11) and an internal 19-amino acid sequence that separates the 20- and 10-kD subunits. Immuno-electron microscopy was performed on human monocytes with immunoglobulins recognizing the active (p20) or precursor (p11) domains of ICE. Elutriated monocytes were stimulated with 50 pM lipopolysaccharide followed by heat-killed Staphylococcus aureus under conditions that induce maximal rates of IL-1 beta secretion. Ultrathin cryosections were cut from fixed frozen pellets of these monocytes and were immunogold labeled with either antibody. Active and precursor domain ICE epitopes were localized in the cytoplasmic ground substance, but they were not detected within the endoplasmic reticulum, the Golgi apparatus, and secretory granules of activated or inactive monocytes. Importantly, numerous ICE p20 epitopes were also observed on the extracellular surfaces of the cell membrane, and were concentrated on the microvilli. Very similar patterns of ICE localization were obtained with unstimulated blood monocytes. In contrast, ICE p11 epitopes were not detected on the surfaces of these monocytes. Likewise, labeling of fixed ultrathin cryosections of monocytes with a biotinylated irreversible ICE inhibitor [Ac-Tyr-Val-Lys(biotin)-Asp-(acyloxy)-methyl-ketone] showed that the compound localized on the outer cell surface as well, and to a lesser extent, within the cytoplasmic ground substance. Furthermore, antipeptide antibodies specific for either the mature or precursor domains of IL-1 beta were both localized upon the cell membrane after stimulation of IL-1 beta secretion. Lipopolysaccaride-primed monocytes that synthesized, but did not secrete IL-1 beta, exhibited only cytoplasmic staining. The data suggests that mature IL-1 beta is generated via cleavage of the 31-kD inactive cytoplasmic IL-1 beta precursor by ICE after association with the plasma membrane during secretion.
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PMID:The interleukin-1 beta-converting enzyme (ICE) is localized on the external cell surface membranes and in the cytoplasmic ground substance of human monocytes by immuno-electron microscopy. 759 15


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