Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amino acid sequence, the positions of the disulfide bonds, and the site of glycosylation for the three subunits of Limulus C-reactive proteins (CRPs) 1.1, 1.4, and 3.3 have been established. The three subunits were shown to exist approximately in equimolar amount and are tightly associated. The hexagonal structure of Limulus CRP, as revealed by electron microscopic studies of Fernandez-Moran et al. (Fernandez-Moran, H., Marchalonis, J., and Edelman, G. M. (1968) J. Mol. Biol. 32, 467-469) might consist of two each of the subunits. The three subunits share an identical amino-terminal sequence of 44 residues and a carboxyl-terminal sequence from residues 206 to 218. Microheterogeneity exists to the extent of 10 to 11% for the entire protein. The positions of 6 half-cystines that form the three disulfide bonds and the site of glycosylation are constant in all subunits. Sequence analyses of peptides derived from enzymatic and chemical cleavages of affinity purified Limulus CRP indicate that subunits other than the three mentioned above exist in the hemolymph. Limulus CRP is therefore polymorphic. Topological analyses of Limulus CRPs, human CRP, rabbit CRP, human amyloid P-component, and Syrian hamster female protein indicate that the seven proteins may originate from the same ancestral gene. Using the topological data generated from the amino acid sequences of the proteins, we calculate that human and Limulus CRPs diverged about 500 million years ago. This figure is in general agreement with the evolutionary distance postulated by anthropological estimation of 400-500 million years.
 ...
PMID:The amino acid sequence of Limulus C-reactive protein. Evidence of polymorphism. 242 65

It has previously been reported that human C-reactive protein (CRP) can exist in at least two molecular conformations distinguished by antigenic, electrophoretic and ligand-binding reactivities. In the present study we describe the formation, detection and distinctiveness of a conformation expressing a CRP neoantigen (neo-CRP), and report that this form is characteristic in vitro of a free CRP subunit. Soluble native-CRP was found to express neo-CRP antigenicity upon treatment with acid; upon urea-chelation or heating in the absence of calcium; and upon adsorption onto uncoated polystyrene plates. Native-CRP bound by capture ELISA to phosphorylcholine-containing ligand or anti-native-CRP did not express neo-CRP antigenicity, suggesting that PC ligand- or antibody binding is not sufficient to induce expression of the neoantigen. Human CRP which expressed neo-CRP antigenicity had limited solubility and tended to aggregate in buffers of ionic strength 0.15, but remained soluble when the ionic strength was reduced to 0.015. Soluble urea-chelated or acid-treated CRP molecules expressing neo-CRP antigenicity chromatographed and electrophoresed as a single protein with a Mr of approx. 22,000, indicating that the CRP neoantigen can be expressed on free CRP subunits and this expression need not require proteolysis. Further, molecules expressing neo-CRP antigenicity were detected in the plasma of patients with rheumatoid arthritis. The identification and characterization of this CRP neoantigen should serve as a useful marker in studies of CRP subunits and biologically relevant forms of CRP, and should contribute to the elucidation of the role of CRP in the acute inflammatory response.
Mol Immunol 1987 May
PMID:Expression, detection and assay of a neoantigen (Neo-CRP) associated with a free, human C-reactive protein subunit. 244 37

The alpha-2-acute phase globulin (alpha 2-APG) of the rat is one of the best investigated acute phase proteins. Glucocorticoids as well as catecholamines could be characterized as potent modulators of alpha 2-APG concentration. The aim of this study was to investigate whether the C-reactive protein (CRP), another acute phase protein important in human medicine, is also influenced by adrenal hormones and if so whether the effects are receptor-mediated or not. Adrenaline and isoproterenol (a beta-agonist) increase the blood level of alpha 2-APG and CRP dose-dependently probably due to a mechanism involved in the sequence of an inflammatory process, too. Dexamethasone administration led to a sigmoidal dose-response curve in the case of alpha 2-APG whereas a biphasic sinusoidal-like dose-response curve was obtained for CRP. Doses around 0.01 mg/kg (2 X 10(-8) Mol/kg) increased while doses around 0.1 mg/kg (2 X 10(-7) Mol/kg) decreased the CRP serum level. By combination of the agonists (adrenaline, dexamethasone) with the respective antagonists (propranolol, a beta-blocking agent and RU 38486, a glucocorticoid antagonist) the agonist-induced changes in concentration of CRP and alpha 2-APG could be suppressed. Therefore it can be assumed that the hormone effects are receptor-mediated ones. The reactions of arthritic or inflamed rats pretreated with RU 38486 indicate a considerable influence of endogenous glucocorticoids on blood levels of acute phase proteins. Taken together, both alpha 2-APG and CRP are modulated by adrenal hormones.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Modulation of rat C-reactive protein serum level by dexamethasone and adrenaline--comparison with the response of alpha 2-acute phase globulin. 245

Human C-reactive protein (CRP) is an acute phase reactant that is selectively deposited at sites of tissue damage. CRP binds with high affinity to purified plasma fibronectin (Fn) when the Fn is immobilized on a surface or matrix via either specific IgG antibody or by gelatin. The CRP to Fn binding is saturable at a molar ratio of CRP/Fn of approximately 9 with a Kd = 1.47 x 10(-7) M and requires Ca2+. The binding site on Fn for CRP was localized to the C-terminal portion by using monoclonal antibodies (mAbs) to Fn as competitive inhibitors of CRP. The binding involves the phosphorylcholine (PC)-binding site of CRP since the addition of PC inhibits binding to Fn and those mAbs to CRP that bind at or near the PC-binding site selectively inhibit the CRP to Fn binding. In addition the mouse IgA myeloma protein TEPC-15, which is specific for PC, also competes with CRP for binding sites on Fn. A mAb to the mouse PC-binding idiotype T-15, which also reacts with the PC-binding site of CRP, inhibits the binding of CRP to Fn. The findings suggest that CRP may play a role in the formation of the extracellular matrix needed for tissue repair. The CRP-Fn interaction may be one of the explanations for the observation of selective deposition of CRP at sites of tissue injury.
Mol Immunol 1988 Aug
PMID:Binding of human C-reactive protein (CRP) to plasma fibronectin occurs via the phosphorylcholine-binding site. 246 Jul 54

The purpose of the study was to determine the temporal relationship between lymphocyte activating factor (LAF) activity and the acute-phase response, as measured by plasma fibronectin (Fn), C-reactive protein (CRP), and albumin levels in adjuvant arthritic rats. LAF activity as measured in the thymocyte costimulator assay, and plasma Fn, CRP, and albumin levels were measured during the acute (Day 3), intermediate (Day 10), and systemic (Day 17) phases of arthritic disease. On Day 3, supernatants from whole spleen cells of adjuvant-injected rats did not exhibit abnormal LAF activity. By Day 10, LAF activity in splenic supernatants from arthritics was significantly (P less than or equal to 0.05) higher than normal, although the increase was no greater than 60%. On Day 17 the LAF activity from arthritic rats had increased an average 300% compared to normals. In contrast to the time course of IL-1 activity, Fn and CRP levels in the arthritic rat were significantly higher than normal at all three time points, although there was a transient fall in Fn and CRP concentrations on Day 10. Plasma albumin levels in arthritic rats were subnormal (P less than or equal to 0.01) on Days 3, 10, and 17, although the concentration of plasma albumin on Day 10 was significantly higher than that measured on Day 3. The acute, intermediate, and systemic phases of adjuvant arthritic paw inflammation paralleled the abnormal profile of Fn, CRP, and albumin concentrations over time. However, LAF activity from arthritic rat spleen cells increased gradually and more closely coincided with the systemic appearance of the disease. Since the appearance of abnormal plasma protein levels in arthritic rats preceded the appearance of increased splenic LAF activity, it appears that there is no causal relationship between enhanced splenic LAF activity and early alteration of plasma Fn, CRP, and albumin levels.
Exp Mol Pathol 1988 Dec
PMID:Lymphocyte activating factor (LAF) and the acute-phase response in adjuvant arthritic rats. 314

Two different crystal forms of human C-reactive protein have been grown from solutions of 2-methyl-2,4-pentanediol. Both crystal forms are tetragonal, the space group for form I is P4(1)22 (or P4(3)22), and that for form II is P4(2)22. The unit cell parameters for form I are a = b = 103.0(5) A, c = 308.5(7) A and for form II are a = b = 103.1(2) A, c = 312.7(6) A. The crystals of form II diffract to at least 3.0 A resolution, and are suitable for detailed structural studies.
J Mol Biol 1987 Aug 05
PMID:Preliminary X-ray study of crystals of human C-reactive protein. 368 76

Three out of four anti-C-reactive protein monoclonal antibodies [HB3-2, (micro, k)], EA4-1 (gamma 2a, k) and FB2-1 (gamma 1, k) bind to C-reactive protein in the presence of 2.5 mM Ca2+ but not in the presence of 1.0 mM EDTA, indicating that the conformation of the antigenic determinant(s) recognized by these three antibodies is dependent upon Ca2+. This Ca2+-dependent binding can be inhibited by 1.0 mM phosphocholine, indicating that this antigenic determinant is at or near the phosphocholine-binding site of C-reactive protein. The binding of the fourth monoclonal antibody [HD2-4 (gamma 2-k)] is independent of the presence of Ca2+ and is not inhibited by phosphocholine. HB3-2 (micro, k) recognizes an antigenic determinant on the structurally related proteins, rabbit CRP and serum amyloid P.
Mol Immunol 1982 Sep
PMID:Demonstration of calcium-induced conformational change(s) in C-reactive protein by using monoclonal antibodies. 618 79

C-reactive protein (CRP) is a trace serum protein which elevates up to 1000-fold in concentration in association with inflammation and tissue necrosis. CRP binds with phosphocholine and phosphate esters; initiates reactions of agglutination, opsonization and complement consumption; and precipitates with protamine and synthetic polymers of lysine and arginine, and these reactivities are modulated by calcium and phosphocholine. We now report on the interactions of heparin with these polycations in the absence and presence of CRP, which show marked similarities to reactions between antigen and antibody. Heparin optimally precipitated with the polycations over a narrow range of reactant ratios, peaking at slight anion charge excess. The complexes formed did not dissociate in excess heparin: however, complex formation was significantly depressed when heparin was added in a single dose in excess of the amount required for optimal precipitation. Calcium did not affect the precipitation of heparin with polycation, and heparin did not precipitate with CRP. However, heparin did induce a rapid and efficient dissociation of CRP-polycation precipitates preformed at equivalence, with total release of CRP. Small amounts of heparin augmented precipitation under conditions of polycation excess of CRP, but as heparin levels were increased to amounts needed to reach equivalence with polycation, CRP was resolubilized in favor of the preferred heparin-polycation complexes. Chondroitin sulfate was similar to heparin in its effects upon the CRP-poly-L-arginine (PLA) interaction, while hyaluronic acid enhanced CRP-PLA precipitation at all concentrations tested and DNA had neither augmenting nor solubilizing effects. These data indicate that CRP-polycation interactions are significantly and selectively influenced in the presence of small amounts of heparin and certain other polyanions. This modulatory reactivity may be of importance in the biological reactivities of CRP during episodes of acute inflammation.
Mol Immunol 1983 May
PMID:Influence of heparin on interactions between C-reactive protein and polycations. 687 43

Homologues of two plasma proteins of vertebrates, alpha 2-macroglobulin and C-reactive protein, participate in a hemolytic system of the ancient arthropod, Limulus polyphemus. C-reactive protein, which can under the appropriate circumstances activate the classical pathway of the mammalian complement system, is an essential element of the hemolytic system of Limulus. The selective removal of C-reactive protein from the plasma with phosphorylethanolamine-agarose inactivated hemolysis. Addition of affinity-purified C-reactive protein to inactive plasma restored activity. Exposure of plasma to phosphorylethanolamine in solution potentiated hemolysis. alpha 2-Macroglobulin is a member of the same protein family as the complement protein C3 and both require an intact thiol ester for activity. Treatment of Limulus plasma with methylamine under conditions that inactivate thiol-ester-containing proteins reduced the hemolytic activity of some plasma preparations. Addition of purified Limulus alpha 2-macroglobulin to the methylamine-treated plasma restored hemolytic activity. However, alpha 2-macroglobulin is not necessary for hemolysis since the hemolytic activity of some pooled plasma preparations was insensitive to methylamine treatment under conditions that inactivated alpha 2-macroglobulin. Purified C-reactive protein was hemolytic in the absence of alpha 2-macroglobulin. These observations suggest that the proteins in Limulus plasma that participate in hemolysis represent the components of an ancient invertebrate defense system with distant evolutionarily affinities to the vertebrate complement system.
Mol Immunol 1993 Jul
PMID:Involvement of alpha 2-macroglobulin and C-reactive protein in a complement-like hemolytic system in the arthropod, Limulus polyphemus. 768 75

Burn death based on circulatory shock is often encountered after recovery from primary shock in patients with deep and extensive burns, i.e., late death. Several toxic substances have been proposed, however, the responsible substance remains obscure. Since we have found leukotoxin, a highly cytotoxic linoleate epoxide biosynthesized by neutrophils, in the burned skin, in the present study we determined plasma leukotoxin concentrations in various degree of 30 burn patients. C-reactive protein and circulatory white blood cells were also measured. A significantly high mortality rate of patients with extensive burns (burn surface area over 70%) was observed compared with that in patients with burn surface area under 70%, and significantly high leukotoxin concentrations were observed within a week, and 3 weeks after the thermal injury in patients with extensive burns compared with those in patients with burn surface area under 70%. There were two peaks of plasma leukotoxin concentrations, i.e., the early phase (within 1 week) and the late phase (over 1 week) in patients with extensive burns. Plasma leukotoxin concentrations significantly correlated with burn surface area in the early phase, and similar correlations were observed in the late phase. A significantly high mortality rate (61%) of patients with peak leukotoxin concentrations over 30 nmol/ml was observed compared with 8% for those below 30 nmol/ml. Plasma leukotoxin concentration correlated significantly to C-reactive protein concentration, log (leukotoxin nmol/ml) = 0.042 x C-reactive protein (mg/dl) + 0.74, (r = 0.83, P < 0.01) in the late phase. From these results, it is concluded that leukotoxin is produced in patients with burns particularly in the late phase of extensive burns, and leukotoxin might play an important role in the tissue destructive procedure associated with severe burns.
Mol Cell Biochem 1994 Oct 26
PMID:Leukotoxin, a linoleate epoxide: its implication in the late death of patients with extensive burns. 786 4


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>