An essential tyrosine residue of <i>Aspergillus</i> polygalacturonase

Stratilová, Eva; Dzúrovä, Mária; Markovič, Oskar; Jörnvall, Hans

doi:10.1016/0014-5793(96)00146-9

Cited by 29 publications

(10 citation statements)

References 16 publications

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“…Our analysis also confirmed the presence of the conserved tyrosine residue (position 586 in PehB) in the C termini of all four exo-PGs, although our full-length PileUp comparison identifies this tyrosine residue in PehX as Y 494 , nine amino acid residues ahead of the one designated by Stratilova et al (58). In addition, several highly conserved amino acid residues and regions are present in the exo-PGs but not in the endo-PGs, suggesting that they may be specific to substrate recognition and terminal polymer cleavage by exo-PGs.…”

Section: Discussionsupporting

confidence: 81%

An exo-poly-alpha-D-galacturonosidase, PehB, is required for wild-type virulence of Ralstonia solanacearum

Huang

Allen

1997

J Bacteriol

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Ralstonia solanacearum, which causes bacterial wilt disease of many plant species, produces several extracellular plant cell wall-degrading enzymes that are suspected virulence factors. These include a previously described endopolygalacturonase (PG), PehA, and two exo-PGs. A gene encoding one of the exo-PGs, pehB, was cloned from R. solanacearum K60. The DNA fragment specifying PehB contained a 2,103-bp open reading frame that encodes a protein of 74.2 kDa with a typical N-terminal signal sequence. The cloned pehB gene product cleaves polygalacturonic acid into digalacturonic acid units. The amino acid sequence of pehB resembles that of pehX, an exo-PG gene from Erwinia chrysanthemi, with 47.2% identity at the amino acid level. PehB also has limited similarity to plant exo-PGs from Zea mays and Arabidopsis thaliana. The chromosomal pehB genes in R. solanacearum wild-type strain K60 and in an endo-PG PehA ؊ strain were replaced with an insertionally inactivated copy of pehB. The resulting mutants were deficient in the production of PehB and of both PehA and PehB, respectively. The pehB mutant was significantly less virulent than the wild-type strain in eggplant virulence assays using a soil inoculation method. However, the pehA mutant was even less virulent, and the pehA pehB double mutant was the least virulent of all. These results suggest that PehB is required for a wild-type level of virulence in R. solanacearum although its individual role in wilt disease development may be minor. Together with endo-PG PehA, however, PehB contributes substantially to the virulence of R. solanacearum.

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Section: Discussionsupporting

confidence: 81%

An exo-poly-alpha-D-galacturonosidase, PehB, is required for wild-type virulence of Ralstonia solanacearum

Huang

Allen

1997

J Bacteriol

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“…These domains are characteristic features of all eukaryotic and prokaryotic polygalacturonases (28,29) and are suggested for substrate binding and enzymatic activity (30 -32). Several other amino acids outside of these domains implicated in enzyme activity (32,33) are also conserved in the Phl p 13 clones (i.e., aspartic acid (D) at position 60, tryptophans (W) at positions 69, 125, 150, and tyrosine (Y) at position 330) (Fig. 1).…”

Section: Sequence Analysis Of Group 13 Allergens Shows That They Belomentioning

confidence: 99%

Molecular Characterization of Polygalacturonases as Grass Pollen-Specific Marker Allergens: Expulsion from Pollen via Submicronic Respirable Particles

Swoboda¹,

Grote

Verdino

et al. 2004

The Journal of Immunology

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Grass pollen belong to the most important allergen sources involved in the elicitation of allergic asthma. We have isolated cDNAs coding for Bermuda grass (Cynodon dactylon) and timothy grass (Phleum pratense) pollen allergens, belonging to a family of pectin-degrading enzymes (i.e., polygalacturonases). The corresponding allergens, termed Cyn d 13 and Phl p 13, represent glycoproteins of ∼42 kDa and isoelectric points of 7.5. rPhl p 13 was expressed in Escherichia coli and purified to homogeneity. Immunogold electron microscopy using rabbit anti-rPhl p 13 Abs demonstrated that in dry pollen group 13, allergens represent primarily intracellular proteins, whereas exposure of pollen to rainwater caused a massive release of cytoplasmic material containing submicronic particles of respirable size, which were coated with group 13 allergens. The latter may explain respiratory sensitization to group 13 allergens and represents a possible pathomechanism in the induction of asthma attacks after heavy rainfalls. rPhl p 13 was recognized by 36% of grass pollen allergic patients, showed IgE binding capacity comparable to natural Phl p 13, and induced specific and dose-dependent basophil histamine release. Epitope mapping studies localized major IgE epitopes to the C terminus of the molecule outside the highly conserved functional polygalacturonase domains. The latter result explains why rPhl p 13 contains grass pollen-specific IgE epitopes and may be used to diagnose genuine sensitization to grass pollen. Our finding that rabbit anti-rPhl p 13 Abs blocked patients’ IgE binding to the allergen suggests that rPhl p 13 may be used for immunotherapy of sensitized patients.

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“…In addition, a Tyr residue at amino acid position 310 in MPG1 is strictly conserved and has been shown to be essential for the activity of PG from Aspergillus spp. (Stratilova et al, 1996). The three deduced sequences differed in their N termini of the predicted mature (after cleavage of the signal peptide) protein.…”

Section: Isolation and Characterization Of Cdnas Encoding Mpg1 Mpg2mentioning

confidence: 99%

Polygalacturonase Gene Expression in Ripe Melon Fruit Supports a Role for Polygalacturonase in Ripening-Associated Pectin Disassembly

et al. 1998

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Ripening-associated pectin disassembly in melon is characterized by a decrease in molecular mass and an increase in the solubilization of polyuronide, modifications that in other fruit have been attributed to the activity of polygalacturonase (PG). Although it has been reported that PG activity is absent during melon fruit ripening, a mechanism for PG-independent pectin disassembly has not been positively identified. Here we provide evidence that pectin disassembly in melon (Cucumis melo) may be PG mediated. Three melon cDNA clones with significant homology to other cloned PGs were isolated from the rapidly ripening cultivar Charentais (C. melo cv Reticulatus F1 Alpha) and were expressed at high levels during fruit ripening. The expression pattern correlated temporally with an increase in pectin-degrading activity and a decrease in the molecular mass of cell wall pectins, suggesting that these genes encode functional PGs. MPG1 and MPG2 were closely related to peach fruit and tomato abscission zone PGs, and MPG3 was closely related to tomato fruit PG. MPG1, the most abundant melon PG mRNA, was expressed in Aspergillus oryzae. The culture filtrate exponentially decreased the viscosity of a pectin solution and catalyzed the linear release of reducing groups, suggesting that MPG1 encodes an endo-PG with the potential to depolymerize melon fruit cell wall pectin. Because MPG1 belongs to a group of PGs divergent from the well-characterized tomato fruit PG, this supports the involvement of a second class of PGs in fruit ripening-associated pectin disassembly.Fruit ripening is a genetically programmed event that is characterized by a number of biochemical and physiological processes that alter fruit color, flavor, aroma, and texture (Brady, 1987). Extensive cell wall modifications occur during ripening and are thought to underlie processes such as fruit softening, tissue deterioration, and pathogen susceptibility. These modifications are regulated at least in part by the expression of genes that encode cell wall-modifying enzymes (Fischer and Bennett, 1991). Pectins are a major class of cell wall polysaccharides that are degraded during ripening, undergoing both solubilization and depolymerization. In tomato the majority of ripeningassociated pectin degradation is attributable to the cell wall hydrolase PG. Transgenic tomato plants with altered PG gene expression indicated that PG-dependent pectin degradation is neither required nor sufficient for tomato fruit softening to occur (Sheehy et al., 1988;Smith et al., 1988;Giovannoni et al., 1989). However, data from experiments using fruit of the same transgenic lines strongly suggested that PG-mediated pectin degradation is important in the later, deteriorative stages of ripening and in pathogen susceptibility of tomato fruit (Schuch et al., 1991;Kramer et al., 1992).In melon (Cucumis melo) substantial amounts of pectin depolymerization and solubilization take place during ripening (McCollum et al., 1989;Ranwala et al., 1992;Rose et al., 1998), implicating a role for PG in...

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An essential tyrosine residue of Aspergillus polygalacturonase

Cited by 29 publications

References 16 publications

An exo-poly-alpha-D-galacturonosidase, PehB, is required for wild-type virulence of Ralstonia solanacearum

An exo-poly-alpha-D-galacturonosidase, PehB, is required for wild-type virulence of Ralstonia solanacearum

Molecular Characterization of Polygalacturonases as Grass Pollen-Specific Marker Allergens: Expulsion from Pollen via Submicronic Respirable Particles

Polygalacturonase Gene Expression in Ripe Melon Fruit Supports a Role for Polygalacturonase in Ripening-Associated Pectin Disassembly

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