Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mannose receptor family comprises four members in mammals, Endo180 (CD280), DEC-205 (CD205), phospholipase A(2) receptor (PLA(2)R) and the mannose receptor (MR, CD206), whose extracellular portion contains a similar domain arrangement: an N-terminal cysteine-rich domain (CysR) followed by a single fibronectin type II domain (FNII) and 8-10 C-type lectin-like domains (CTLDs). These proteins mediate diverse functions ranging from extracellular matrix turnover through collagen uptake to homeostasis and immunity based on sugar recognition. Endo180 and the MR are multivalent transmembrane receptors capable of interacting with multiple ligands; in both receptors FNII recognizes collagens, and a single CTLD retains lectin activity (CTLD2 in Endo180 and CTLD4 in MR). It is expected that the overall conformation of these multivalent molecules would deeply influence their function as the availability of their binding sites could be altered under different conditions. However, conflicting reports have been published on the three-dimensional arrangement of these receptors. Here, we have used single particle electron microscopy to elucidate the three-dimensional organization of the MR and Endo180. Strikingly, we have found that both receptors display distinct three-dimensional structures, which are, however, conceptually very similar: a bent and compact conformation built upon interactions of the CysR domain and the lone functional CTLD. Biochemical and electron microscopy experiments indicate that, under a low pH mimicking the endosomal environment, both MR and Endo180 experience large conformational changes. We propose a structural model for the mannose receptor family where at least two conformations exist that may serve to regulate differences in ligand selectivity.
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PMID:Structural model for the mannose receptor family uncovered by electron microscopy of Endo180 and the mannose receptor. 1645 73

The level of an inhibitor of tissue-type plasminogen activator (t-PA) increased slowly during the early developmental stage of seeds of Erythrina caffra Thunb. Thereafter, the inhibitor increased exponentially until the seeds reached maturity. At maturity, the t-PA inhibitor levels in the cotyledons were 38 times higher than the levels at the onset of seed development. The t-PA inhibitor accumulated at a faster rate than the storage proteins, which reached a concentration 15 times higher than the protein concentration at the onset of seed development. During the imbibition and germination process, the t-PA inhibitor decreased gradually. The inhibitor kept on decreasing during the growth of the seedlings until the 10th day after imbibition, when it leveled off at 4.1% of that of the initial inhibitor concentration. The inhibitor remained at this level until the cotyledons were shed at day 22. The total protein in the cotyledons decreased at a slower rate than the inhibitor and reached a minimum concentration at day 20 of 3.6% of the initial protein concentration in the cotyledons. Callus cultures of root, shoot, leaf, and cotyledonary tissue was established and maintained on Murashige-Skoog medium supplemented with 3% sucrose, 10 micromolar benzyladenine, and 5 micromolar 2,4-dichlorophenoxyacetic acid. A shoot cell suspension culture was established on Murashige-Skoog medium supplemented with 3% sucrose, 1 micromolar benzyladenine, and 0.5 micromolar 2,4-dichlorophenoxyacetic acid (pH 5.7) and shaken at 60 revolutions per minute. The level of t-PA inhibitor in root, shoot, leaf, and cotyledonary callus was substantially lower than in the corresponding intact tissue. The t-PA inhibitor levels in the linear growth phase was higher than in the lag or stationary growth phases of the cell suspension culture. A hydrolysate of the cell walls of tomato and E. caffra Thunb, as well as polyamines and organic acids, did not increase the concentration of t-PA inhibitor in suspension cultures or intact leaf tissue of E. caffra. The t-PA inhibitor levels of suspension cultures were increased by Na(2)SO(4) but not by I-cysteine in the nutrient medium.
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PMID:Occurrence of an Inhibitor of Tissue-Type Plasminogen Activator in Seeds and in Vitro Cultures of Erythrina caffra Thunb. 1666 12

We report the cloning and sequence analysis of BA-5A from a venom gland cDNA library of the puff adder, Bitis arietans, that encodes a novel ECD-disintegrin-like domain. BA-5A is a unique PII disintegrin. It contains the 16 cysteine residues that are conserved in all known disintegrin-like domains of ADAM proteins and snake venom metalloproteinases but lacks the cysteine-rich domain. These features suggest that BA-5A may represent an intermediate in the evolutionary pathway of the long disintegrin bitistatin and that removal of the cysteine-rich domain and loss of the PIII-specific disulfide bond were separate events along the structural diversification pathway of disintegrins, the former predating the latter. The protein family composition of the Bitis arietans venom, as determined by combination of reversed-phase HPLC and proteomic analysis, was as follows: Zn(2+)-metalloproteinase (38.5%), serine proteinase (19.5%), disintegrin (17.8%), C-type lectin-like (13.2%), PLA(2) (4.3%), Kunitz-type inhibitor (4.1%), cystatin (1.7%), and unknown (0.9%). BA-5A could not be detected in the venom proteome of Bitis arietans. The occurrence of this very low-abundance (< 0.05%) or nonexpressed disintegrin transcript indicates a hitherto unrecognized structural diversity of this protein family. Whether BA-5A plays a physiological role or represents an orphan protein which could eventually evolve a role in the adaptation of snakes to changing ecological niches and prey habits deserves further investigation.
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PMID:Molecular cloning of disintegrin-like transcript BA-5A from a Bitis arietans venom gland cDNA library: a putative intermediate in the evolution of the long-chain disintegrin bitistatin. 1678 36

Bothrops snake venoms contain a variety of phospholipases (PLA(2)), some of which are myotoxic. In this work, we used reverse-phase HPLC and mass spectrometry to purify and sequence two PLA(2) from the venom of Bothrops insularis. The two enzymes, designated here as BinTX-I and BinTx-II, were acidic (pI 5.05 and 4.49) Asp49 PLA(2), with molecular masses of 13,975 and 13,788, respectively. The amino acid sequence and molecular mass of BinTX-I were identical to those of a PLA(2) previously isolated from this venom (PA2_BOTIN, SwissProt accession number ) while those of BinTX-II indicated that this was a new enzyme. Multiple sequence alignments with other Bothrops PLA(2) showed that the amino acids His48, Asp49, Tyr52 and Asp99, which are important for enzymatic activity, were fully conserved, as were the 14 cysteine residues involved in disulfide bond formation, in addition to various other residues. A phylogenetic analysis showed that BinTX-I and BinTX-II grouped with other acidic Asp49 PLA(2) from Bothrops venoms, and computer modeling indicated that these enzymes had the characteristic structure of bothropic PLA(2) that consisted of three alpha-helices, a beta-wing, a short helix and a calcium-binding loop. BinTX-I (30 microg/paw) produced mouse hind paw edema that was maximal after 1h compared to after 3h with venom (10 and 100 microg/paw); in both cases, the edema decreased after 6h. BinTX-1 and venom (40 microg/ml each) produced time-dependent neuromuscular blockade in chick biventer cervicis preparations that reached 40% and 95%, respectively, after 120 min. BinTX-I also produced muscle fiber damage and an elevation in CK, as also seen with venom. These results indicate that BinTX-I contributes to the neuromuscular activity and tissue damage caused by B. insularis venom in vitro and in vivo.
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PMID:Purification, sequencing and structural analysis of two acidic phospholipases A2 from the venom of Bothrops insularis (jararaca ilhoa). 1714 Jul 21

A novel serine protease with fibrinolytic activity named CSP was purified from the culture supernatant of the fungus Cordyceps sinensis, a kind of Chinese herbal medicine. Analysis of the purified enzyme by SDS-PAGE indicated that CSP was a single polypeptide chain with an apparent molecular weight of 31 kDa, and N-terminal sequencing revealed that the first ten amino acid residues of the enzyme were Ala-Leu-Ala-Thr-Gln-His-Gly-Ala-Pro-Trp-. When casein was used as a substrate, the proteolytic activity of CSP reached its maximum at pH 7.0 and 40 degrees C. The effect of chemical agents on the enzyme activity indicated that CSP is a serine protease with a free cysteine residue near the active site. It hydrolysed fibrinogen, fibrin and casein with a high efficiency, while hydrolysing bovine serum albumin (BSA) and human serum albumin (HSA) to a lesser extent. CSP was found to be a plasmin-like protease, but not a plasminogen activator, and it preferentially cleaved the A alpha chain of fibrinogen and the alpha-chain of fibrin. Therefore, the extracellular protein CSP may represent a potential new therapeutic agent for the treatment of thrombosis.
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PMID:A novel extracellular protease with fibrinolytic activity from the culture supernatant of Cordyceps sinensis: purification and characterization. 1766 28

We report the comparative proteomic characterization of the venoms of two related neotropical arboreal pitvipers from Costa Rica of the genus Bothriechis, B. lateralis (side-striped palm pit viper) and B. schlegelii (eyelash pit viper). The crude venoms were fractionated by reverse-phase HPLC, followed by analysis of each chromatographic fraction by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of tryptic peptides. The venom proteomes of B. lateralis and B. schlegelii comprise similar number of distinct proteins belonging, respectively, to 8 and 7 protein families. The two Bothriechis venoms contain bradykinin-potentiating peptides (BPPs), and proteins from the phospholipase A 2 (PLA 2), serine proteinase, l-amino acid oxidase (LAO), cysteine-rich secretory protein (CRISP), and Zn (2+)-dependent metalloproteinase (SVMP) families, albeit each species exhibit different relative abundances. Each venom also contains unique components, for example, snake venom vascular endothelial growth factor (svVEGF) and C-type lectin-like molecules in B. lateralis, and Kazal-type serine proteinase inhibitor-like proteins in B. schlegelii. Using a similarity coefficient, we estimate that the similarity of the venom proteins between the two Bothriechis taxa may be <10%, indicating a high divergence in their venom compositions, in spite of the fact that both species have evolved to adapt to arboreal habits. The major toxin families of B. lateralis and B. schlegelii are SVMP (55% of the total venom proteins) and PLA 2 (44%), respectively. Their different venom toxin compositions provide clues for rationalizing the distinct signs of envenomation caused by B. schlegelii and B. lateralis. An antivenomic study of the immunoreactivity of the Instituto Clodomiro Picado (ICP) polyvalent antivenom toward Bothriechis venoms revealed that l-amino acid oxidase and SVMPs represent the major antigenic protein species in both venoms. Our results provide a ground for rationalizing the reported protection of the ICP polyvalent antivenom against the hemorrhagic, coagulant, defibrinating, caseinolytic and fibrin(ogen)olytic activities of Bothriechis ( schlegelii, lateralis) venoms. However, these analyses also evidenced the limited recognition capability of the polyvalent antivenom toward a number of Bothriechis venom components, predominantly BPPs, svVEGF, Kazal-type inhibitors, some PLA 2 proteins, some serine proteinases, and CRISP molecules.
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PMID:Snake venomics and antivenomics of the arboreal neotropical pitvipers Bothriechis lateralis and Bothriechis schlegelii. 1844 72

BmTX-I, an Asp49 phospholipase A(2), was purified from Bothrops moojeni venom after only one chromatographic step using reverse-phase HPLC on mu-Bondapak C-18 column. A molecular mass of 14238.71Da was determined by MALDI-TOF mass spectrometry. Amino acid analysis showed a high content of hydrophobic and basic amino acids as well as 14 half-cysteine residues. The BmTX-I PLA(2) had a sequence of 121 residues of amino acids: DLWQFNKMIK KEVGKLPFPF YGAYGCYCGW GGRGEKPKDG TDRCCFVHDC CYKKLTGCPK WDDRYSYSWK DITIVCGEDL PCEEICECDR AAAVCFYENL GTYNKKYMKH LKPCKKADYP C and pI value 7.84, and showed a high degree of homology with basic Asp49 PLA(2) myotoxins from other Bothrops venoms. BmTX-I presented PLA(2) activity in the presence of a synthetic substrate and showed a minimum sigmoidal behavior, reaching its maximal activity at pH 8.0 and 35-45 degrees C. Maximum PLA(2) activity required Ca(2+) and in the presence of Mg(2+), Cd(2+) and Mn(2+) it was reduced in presence or absence of Ca(2+). Crotapotin from Crotalus durissus colillineatus rattlesnake venom has significantly inhibited (P<0.05) the enzymatic activity of BmTX-I. In vitro, the whole venom and BmTX-I caused a blockade of the neuromuscular transmission in young chick biventer cervicis preparations in a similar way to other bothrops species. In mice, BmTX-I and the whole venom-induced myonecrosis and a systemic interleukin-6 response upon intramuscular injection. Edema-forming activity was also analyzed through injection of the venom and the purified BmTX-I into the subplantar region of the right footpad. Since BmTX-I exert a strong proinflammatory effect; the enzymatic phospholipids hydrolysis might be relevant for these phenomena.
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PMID:Biological and biochemical characterization of new basic phospholipase A(2) BmTX-I isolated from Bothrops moojeni snake venom. 1850 40

A novel biodegradable diblock copolymer, poly(L-cysteine)-b-poly(L-lactide) (PLC-b-PLLA), was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydride of beta-benzyloxycarbonyl-L-cysteine (ZLC-NCA) with amino-terminated poly(L-lactide) (NH 2-PLLA) as a macroinitiator in a convenient way. The diblock copolymer and its precursor were characterized by (1)H NMR, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS) measurements. The length of each block polymer could be tailored by molecular design and the ratios of feeding monomers. The cell adhesion and cell spread on the PZLC-b-PLLA and PLC-b-PLLA films were enhanced compared to those on pure PLA film. PLC-b-PLLA can self-assemble to form micelles in aqueous media. A pyrene probe is used to demonstrate the micelle formation of PLC-b-PLLA in aqueous solution. Due to the ease of disulfide exchange with thiols, the obtained micelles are reversible shell cross-linked (SCL) micelles. The morphology and size of the micelles are studied by dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM).
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PMID:Formation of reversible shell cross-linked micelles from the biodegradable amphiphilic diblock copolymer poly(L-cysteine)-block-poly(L-lactide). 1869 58

We report the proteomic characterization of venom of the pitvipers Bothrops cotiara and Bothrops fonsecai. Crude venoms were fractionated by reverse-phase HPLC, followed by SDS-PAGE, N-terminal sequencing, MALDI-TOF mass fingerprinting, and CID-MS/MS. Each venom contained around 30 proteins in the range of 7-110 kDa belonging to only 8 (B. cotiara) and 9 (B. fonsecai) families which may target the hemostatic system, albeit distinctly distributed among the two species. B. cotiara and B. fonsecai share medium-sized disintegrins, disintegrin-like/cysteine-rich (DC) fragments, snake venom vascular endothelial growth factor, cysteine-rich secretory proteins, serine proteinases, C-type lectins, l-amino acid oxidase, and Zn(2+)-dependent metalloproteinases. In addition, B. fonsecai expresses a high abundance PLA(2) molecule (13,890 Da), whereas PLA(2) molecules were not detected in B. cotiara's venom. This striking finding is in line with previous biochemical analyses showing the absence of phospholipasic activity in the venom of B. cotiara. The potential adaptive significance of the lack of PLA(2) molecules is enigmatic, and alternative explanations are discussed. B. fonsecai is morphologically extremely similar to B. cotiara. Our comparative proteomic analysis shows that compositional differences between their venoms can be employed as a taxonomy signature for unambiguous species identification independently of geographic origin and morphological characteristics.
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PMID:Snake venomics of the Brazilian pitvipers Bothrops cotiara and Bothrops fonsecai. Identification of taxonomy markers. 1876 Mar 86

H-Rev107 is a protein that was previously cloned as a negative regulator of proto-oncogene Ras and classified as a class II tumor suppressor. Its structural similarity to lecithin retinol acyltransferase and Ca2+-independent phosphatidylethanolamine (PE) N-acyltransferase led us to analyze H-Rev107 as an enzyme involved in phospholipid metabolism. Here, we show that recombinant H-Rev107s from rat, human, and mouse possess phospholipase (PL) A1 or A2 activity toward phosphatidylcholine (PC). Further examination with purified recombinant protein revealed that H-Rev107 functions as a cytosolic Ca2+-independent PLA(1/2) for PC and PE with higher PLA1 activity than PLA2 activity. Dithiothreitol and iodoacetic acid exhibited stimulatory and inhibitory effects, respectively. Histidine-21 and cysteine-111 of rat H-Rev107 were presumed to form a catalytic dyad based on database analysis, and their single mutants were totally inactive. These results suggested that H-Rev107 is a hydrolase of the thiol type. The N-terminal proline-rich and C-terminal hydrophobic domains of H-Rev107 were earlier reported to be responsible for the regulation of cell proliferation. Analysis of deletion mutants indicated that these domains are also catalytically essential, suggesting relevance of the catalytic activity to the anti-proliferative activity.
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PMID:The tumor suppressor gene H-Rev107 functions as a novel Ca2+-independent cytosolic phospholipase A1/2 of the thiol hydrolase type. 1904 60


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