scholarly journals The membrane-bound histidine acid phosphatase TbMBAP1 is essential for endocytosis and membrane recycling in Trypanosoma brucei

2005 ◽  
Vol 118 (10) ◽  
pp. 2105-2118 ◽  
Author(s):  
M. Engstler
Keyword(s):  
Acid Phosphatase ◽  
Trypanosoma Brucei ◽  
Membrane Recycling ◽  
Histidine Acid Phosphatase ◽  
Membrane Bound

scholarly journals N-Glycosylation Improves the Pepsin Resistance of Histidine Acid Phosphatase Phytases by Enhancing Their Stability at Acidic pHs and Reducing Pepsin's Accessibility to Its Cleavage Sites

2015 ◽  
Vol 82 (4) ◽  
pp. 1004-1014 ◽  
Author(s):  
Canfang Niu ◽  
Huiying Luo ◽  
Pengjun Shi ◽  
Huoqing Huang ◽  
Yaru Wang ◽  
...  
Keyword(s):  
Acid Phosphatase ◽  
Biochemical Characterization ◽  
Animal Feed ◽  
Glycosylation Site ◽  
Site Directed Mutagenesis ◽  
Acidic Ph ◽  
Cleavage Sites ◽  
Ph Optimum ◽  
Content Type ◽  
Histidine Acid Phosphatase

ABSTRACTN-Glycosylation can modulate enzyme structure and function. In this study, we identified two pepsin-resistant histidine acid phosphatase (HAP) phytases fromYersinia kristensenii(YkAPPA) andYersinia rohdei(YrAPPA), each having anN-glycosylation motif, and one pepsin-sensitive HAP phytase fromYersinia enterocolitica(YeAPPA) that lacked anN-glycosylation site. Site-directed mutagenesis was employed to construct mutants by altering theN-glycosylation status of each enzyme, and the mutant and wild-type enzymes were expressed inPichia pastorisfor biochemical characterization. Compared with those of theN-glycosylation site deletion mutants andN-deglycosylated enzymes, allN-glycosylated counterparts exhibited enhanced pepsin resistance. Introduction of theN-glycosylation site into YeAPPA as YkAPPA and YrAPPA conferred pepsin resistance, shifted the pH optimum (0.5 and 1.5 pH units downward, respectively) and improved stability at acidic pH (83.2 and 98.8% residual activities at pH 2.0 for 1 h). Replacing the pepsin cleavage sites L197 and L396 in the immediate vicinity of theN-glycosylation motifs of YkAPPA and YrAPPA with V promoted their resistance to pepsin digestion when produced inEscherichia colibut had no effect on the pepsin resistance ofN-glycosylated enzymes produced inP. pastoris. Thus,N-glycosylation may improve pepsin resistance by enhancing the stability at acidic pH and reducing pepsin's accessibility to peptic cleavage sites. This study provides a strategy, namely, the manipulation ofN-glycosylation, for improvement of phytase properties for use in animal feed.

Developmental regulation of a novel repetitive protein of Trypanosoma brucei

1987 ◽  
Vol 7 (8) ◽  
pp. 2838-2844
Author(s):  
M R Mowatt ◽  
C E Clayton
Keyword(s):  
Trypanosoma Brucei ◽  
Tandem Repeats ◽  
Signal Sequence ◽  
Developmental Regulation ◽  
Developmentally Regulated ◽  
Hydrophobic Domain ◽  
Reading Frame ◽  
Amino Terminal ◽  
Membrane Bound

Trypanosoma brucei undergoes many morphological and biochemical changes during transformation from the bloodstream trypomastigote to the insect procyclic trypomastigote form. We cloned and determined the complete nucleotide sequence of a developmentally regulated cDNA. The corresponding mRNA was abundant in in vitro-cultivated procyclics but absent in bloodstream forms. The trypanosome genome contains eight genes homologous to this cDNA, arranged as four unlinked pairs of tandem repeats. The longest open reading frame of the cDNA predicts a protein of 15 kilodaltons, the central portion of which consists of 29 tandem glutamate-proline dipeptides. The repetitive region is preceded by an amino-terminal signal sequence and followed by a hydrophobic domain that could serve as a membrane anchor; the mRNA was found on membrane-bound polyribosomes. These results suggest that the protein is membrane associated.

Trypanosoma brucei: Ecto-Phosphatase Activity Present on the Surface of Intact Procyclic Forms

1997 ◽  
Vol 52 (5-6) ◽  
pp. 351-358 ◽  
Author(s):  
Eloise C. Fernandes ◽  
José R. Meyer-Fernandes ◽  
Mário A. C. Silva-Neto ◽  
Anibal E. Vercesi
Keyword(s):  
Acid Phosphatase ◽  
Cell Surface ◽  
Cell Viability ◽  
Phosphatase Activity ◽  
Trypanosoma Brucei ◽  
Intact Cells ◽  
Vanadate Inhibition ◽  
Rate Of Hydrolysis ◽  
Ph Range

Abstract The results presented in this paper indicate that procyclic forms of Trypanosoma brucei possess a phosphatase activity detected in the external cell surface able to hydrolyze about 0.7 nmol ∙ mg−1. min−1 p-nitrophenylphosphate. A faster rate of hydrolysis was observed when membrane-enriched fractions were used. This activity is weakly sensitive to 1 mᴍ NaF, 10 mᴍ tartrate and 10 mᴍ levamizole but strongly inhibited by 0.1 mᴍ vanadate. Inhibition by both NaF and vanadate have a competitive character. This phosphatase activity decreases by increasing the pH from 6.8 to 8.4, a pH range in which cell viability was maintained during at least 1 hour. In the membrane-enriched fractions this phosphatase activity showed to be an acid phosphatase. In addition, intact cells could catalyze the dephosphorylation of [32P]phosphocasein phosphorylated at serine and threonine residues.

The fine structure and selected histochemistry of ungerminated basidiospores of Agrocybe acericola

1996 ◽  
Vol 74 (5) ◽  
pp. 780-787 ◽  
Author(s):  
Donald G. Ruch ◽  
Kiki Nurtjahja
Keyword(s):  
Fine Structure ◽  
Acid Phosphatase ◽  
Glyoxylate Cycle ◽  
Outer Wall ◽  
Spore Wall ◽  
Malate Synthase ◽  
Marker Enzyme ◽  
Wall Ultrastructure ◽  
Membrane Bound ◽  
The Glyoxylate Cycle

The basidiospore wall of Agrocybe acericola is composed of two distinct layers that are continuous around the spores. At the germ pore, the outer wall is very thin and the inner wall becomes thicker. The plasma membrane is appressed to the inner wall and lacks distinct invaginations. The protoplasm is densely packed with ribosomes. Spores contain very little lipid distributed at each end. Mitochondria are well defined and distributed throughout the cytoplasm. Spores are binucleate, with the two nuclei lying on a line nearly perpendicular to the long axis of the cell. Various sizes of single membrane-bound vacuoles are widely distributed in the cytoplasm. These vacuoles were shown to contain acid phosphatase, indicating lysosomal activity. Microbody-like organelles are observed, which are probably glyoxysomes, since assays of malate synthase, a marker enzyme of the glyoxylate cycle, are positive. Keywords: Agrocybe, spore wall ultrastructure, basidiospore ultrastructure, glyoxylate cycle, malate synthase, acid phosphatase.

Structural and enzymatic characterization of plant zymogen bodies

1971 ◽  
Vol 49 (11) ◽  
pp. 2053-2057 ◽  
Author(s):  
Esther Cohen ◽  
Y. Shain ◽  
Y. Ben-Shaul ◽  
A. M. Mayer
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Galactosidase Activity ◽  
Enzymatic Characterization ◽  
Subcellular Organelles ◽  
Inactive Form ◽  
Optimum Ph ◽  
Membrane Bound ◽  
Pea Seeds

The zymogen body fraction of pea seeds was further investigated as to the content and localization of additional enzymes. This fraction was previously shown to contain an inactive form of amylopectin-1,6-glucosidase. An acid phosphatase was found with an optimum pH of 5.4. ATP or GTP were the preferred natural substrates, although there was no effect of Mg2+, K+, or Na+ ions on this acid nucleotide phosphatase activity. Cytochemical methods show that the ATPase is membrane-bound and that these bodies have only a single limiting membrane. No RNAse activity could be found; however, there was considerable β-galactosidase activity. It is concluded that these zymogen bodies are a distinct class of subcellular organelles in plants.

Purification and characterization of a membrane-bound acid phosphatase of Leishmania mexicana

1991 ◽  
Vol 47 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Beatrice Menz ◽  
Gerhard Winter ◽  
Thomas Ilg ◽  
Friedrich Lottspeich ◽  
Peter Overath
Keyword(s):  
Acid Phosphatase ◽  
Leishmania Mexicana ◽  
Purification And Characterization ◽  
Membrane Bound

scholarly journals Crystallization and preliminary crystallographic analysis of the major acid phosphatase fromLegionella pneumophila

2015 ◽  
Vol 71 (6) ◽  
pp. 779-783 ◽  
Author(s):  
Dan Zhou ◽  
Yang Pan ◽  
Xiaofang Chen ◽  
Nannan Zhang ◽  
Honghua Ge
Keyword(s):  
Acid Phosphatase ◽  
Unit Cell ◽  
Diffusion Method ◽  
Phosphoryl Group ◽  
Sequence Motif ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Histidine Acid Phosphatase ◽  
Major Acid

The major acid phosphatase fromLegionella pneumophila(LpMAP) belongs to the histidine acid phosphatase superfamily. It contains the characteristic histidine acid phosphatase (HAP) sequence motif RHGXRXP responsible for the hydrolysis of a phosphoryl group from phosphate monoesters under acidic conditions. Here, the crystallization and preliminary X-ray analysis of crystals ofLpMAP in the apo form and in complex with L-(+)-tartrate are described. By using the hanging-drop vapour-diffusion method, apoLpMAP andLpMAP–tartrate were crystallized in space groupP21, with unit-cell parametersa= 91.50,b= 56.48,c= 146.35 Å, β = 110.01°, and in space groupP1, with unit-cell parametersa= 55.51,b= 73.51 ,c= 98.78 Å, α = 78.82, β = 77.65, γ = 67.73°, respectively. Diffraction data were collected at 100 K and the phases were determined using the molecular-replacement method.

Compartmentation of enzymes in a microbody, the glycosome, is essential in Trypanosoma brucei

2002 ◽  
Vol 115 (13) ◽  
pp. 2651-2658
Author(s):  
Cristina Guerra-Giraldez ◽  
Luis Quijada ◽  
Christine E. Clayton
Keyword(s):  
Rna Interference ◽  
Trypanosoma Brucei ◽  
Metabolic Pathways ◽  
Mammalian Cells ◽  
Atp Synthesis ◽  
Bloodstream Form ◽  
Matrix Proteins ◽  
Selective Media ◽  
Atp Generation ◽  
Membrane Bound

All kinetoplastids contain membrane-bound microbodies known as glycosomes,in which several metabolic pathways including part of glycolysis are compartmentalized. Peroxin 2 is essential for the import of many proteins into the microbodies of yeasts and mammals. The PEX2 gene of Trypanosoma brucei was identified and its expression was silenced by means of tetracycline-inducible RNA interference. Bloodstream-form trypanosomes, which rely exclusively on glycolysis for ATP generation, died rapidly upon PEX2 depletion. Insect-form (procyclic) trypanosomes do not rely solely on glycolysis for ATP synthesis. PEX2 depletion in procyclic forms resulted in relocation of most tested matrix proteins to the cytosol, and these mutants also died. Compartmentation of microbody enzymes is therefore essential for survival of bloodstream and procyclic T. brucei. In contrast, yeasts and cultured mammalian cells grow normally in the absence of peroxisomal membranes unless placed on selective media.

Identification and partial characterization of an extracellular acid phosphatase activity of Leishmania donovani promastigotes

1982 ◽  
Vol 2 (1) ◽  
pp. 76-81
Author(s):  
M Gottlieb ◽  
D M Dwyer
Keyword(s):  
Acid Phosphatase ◽  
Leishmania Donovani ◽  
Surface Membrane ◽  
Extracellular Enzyme ◽  
Growth Cycle ◽  
Growth Media ◽  
Ph Optimum ◽  
Membrane Bound ◽  
Extracellular Acid Phosphatase

An extracellular acid phosphatase was detected in the growth media of Leishmania donovani promastigotes. The enzyme was released at all stages of the growth cycle and in amounts which accounted for 90% of the total amount of this enzyme in the culture. The exoenzyme exhibited a pH optimum of 4.5 to 5.0 and was active with a variety of organic phosphates. The enzymatic activity was excluded from Sephacryl S-300 and was retained by ultrafilters with nominal molecular weight cutoffs of up to 300,000. The results of comparative studies indicated that the extracellular enzyme was distinct from a surface membrane-bound acid phosphatase of L. donovani promastigotes which has been previously described.

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