Three α‐Galactosidase Genes of <i>Trichoderma reesei</i> Cloned by Expression in Yeast

Margolles-Clark, Emilio; Tenkanen, Maija; Luonteri, Elina; Penttilä, Merja

doi:10.1111/j.1432-1033.1996.0104h.x

Cited by 91 publications

(76 citation statements)

References 47 publications

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“…However, one possible member of GH54, ␣-L-arabino- furanosidase from H. jecorina PC-3-7 (HjPCAbf), is reported to contain a non-catalytic xylan-binding domain in its C-terminal 18-kDa portion, which can be proteolytically cleaved by pepsin (37). HjPCAbf is probably a member of GH54 because its Nterminal amino acid sequence is almost identical to that of GH54 ␣-L-arabinofuranosidase/␤-xylosidase from H. jecorina RutC-30 (HjRuAbf) (38). Therefore, the xylan-binding domain of HjPCAbf seems to correspond to the ABD of AkAbfB.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure of a Family 54 α-l-Arabinofuranosidase Reveals a Novel Carbohydrate-binding Module That Can Bind Arabinose

Miyanaga

Koseki

Matsuzawa

et al. 2004

Journal of Biological Chemistry

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As the first known structures of a glycoside hydrolase family 54 (GH54) enzyme, we determined the crystal structures of free and arabinose-complex forms of Aspergillus kawachii IFO4308 ␣-L-arabinofuranosidase (AkAbfB). AkAbfB comprises two domains: a catalytic domain and an arabinose-binding domain (ABD). The catalytic domain has a ␤-sandwich fold similar to those of clan-B glycoside hydrolases. ABD has a ␤-trefoil fold similar to that of carbohydrate-binding module (CBM) family 13. However, ABD shows a number of characteristics distinctive from those of CBM family 13, suggesting that it could be classified into a new CBM family. In the arabinose-complex structure, one of three arabinofuranose molecules is bound to the catalytic domain through many interactions. Interestingly, a disulfide bond formed between two adjacent cysteine residues recognized the arabinofuranose molecule in the active site. From the location of this arabinofuranose and the results of a mutational study, the nucleophile and acid/ base residues were determined to be Glu 221 and Asp 297 , respectively. The other two arabinofuranose molecules are bound to ABD. The O-1 atoms of the two arabinofuranose molecules bound at ABD are both pointed toward the solvent, indicating that these sites can both accommodate an arabinofuranose side-chain moiety linked to decorated arabinoxylans.

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Section: Resultsmentioning

confidence: 99%

Crystal Structure of a Family 54 α-l-Arabinofuranosidase Reveals a Novel Carbohydrate-binding Module That Can Bind Arabinose

Miyanaga

Koseki

Matsuzawa

et al. 2004

Journal of Biological Chemistry

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“…For example, recent work with ␣-galactosidases has indicated that these enzymes fill an essential role in the breakdown of side chains from large oligosaccharides such as hemicellulose and soy (10,16). These enzymes are intracellular and are induced after breakdown of the target substrate's polymer backbone by extracellular enzymes such as ␤-mannanase (18). Both ␣-and ␤-linkages are common in the side chains of sugar polymers produced by plants and in the complex saccharides adsorbed to humic acid substances in the soil.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicola Strain BA

Coombs

Brenchley

2001

Appl Environ Microbiol

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Three genes with homology to glycosyl hydrolases were detected on a DNA fragment cloned from a psychrophilic lactic acid bacterium isolate, Carnobacterium piscicola strain BA. A 2.2-kb region corresponding to an ␣-galactosidase gene, agaA, was followed by two genes in the same orientation, bgaB, encoding a 2-kb ␤-galactosidase, and bgaC, encoding a structurally distinct 1.76-kb ␤-galactosidase. This gene arrangement had not been observed in other lactic acid bacteria, including Lactococcus lactis, for which the genome sequence is known. To determine if these sequences encoded enzymes with ␣-and ␤-galactosidase activities, we subcloned the genes and examined the enzyme properties. The ␣-galactosidase, AgaA, hydrolyzes para-nitrophenyl-␣-Dgalactopyranoside and has optimal activity at 32 to 37°C. The ␤-galactosidase, BgaC, has an optimal activity at 40°C and a half-life of 15 min at 45°C. The regulation of these enzymes was tested in C. piscicola strain BA and activity on both ␣-and ␤-galactoside substrates decreased for cells grown with added glucose or lactose. Instead, an increase in activity on a phosphorylated ␤-galactoside substrate was found for the cells supplemented with lactose, suggesting that a phospho-galactosidase functions during lactose utilization. Thus, the two ␤-galactosidases may act synergistically with the ␣-galactosidase to degrade other polysaccharides available in the environment.Glycosyl hydrolases (EC 3.2.1 to 3.2.3) cleave the glycosidic bond(s) between two or more carbohydrates or the bond between a carbohydrate moiety and a noncarbohydrate moiety. Traditionally, glycosyl hydrolases were grouped together based on substrate specificity. For example, all ␤-galactosidases were combined into one group (EC 3.2.1.23) because of their shared ability to hydrolyze lactose. However, classification based on substrate specificity is complicated by the fact that some enzymes hydrolyze more than one substrate. Some glycosyl hydrolases have activity on both phosphorylated and nonphosphorylated substrates (3, 21) or on ␤-glucosides and ␤-galactosides (2) and some ␤-galactosidases have activity on ␤-fucosides and ␤-galacturonides (11,15, 25).The increase in the number of sequenced glycosyl hydrolases and the availability of new analytical methods has permitted the reorganization of these enzymes into families based on amino acid sequence similarities and hydrophobic cluster analysis (12,13,14). There are presently four families containing enzymes with ␤-galactosidase activity, families 1, 2, 35, and 42, and three families which contain enzymes with ␣-galactosidase activity, families 4, 27, and 36. New glycosyl hydrolases which have been sequenced can be grouped into a specific family on the basis of DNA or deduced amino acid similarity. In many cases, however, there is no information to verify the substrate specificity of the enzymes within these groups or their possible role(s) in cellular metabolism.

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“…In addition to enzymes with cellulolytic activity, a number of enzymes have been identified in T. reesei that degrade hemicellulose (17,(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). These enzymes include four xylanases (Xyn1, Xyn2, Xyn3, and Xyn4) and mannanase (Man1), which cleave the xylan and mannan main chains of hemicellulose.…”

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confidence: 99%

Transcriptional Regulation of Biomass-degrading Enzymes in the Filamentous Fungus Trichoderma reesei

Foreman¹,

Brown

Dankmeyer³

et al. 2003

Journal of Biological Chemistry

427

341

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The filamentous fungus Trichoderma reesei produces and secretes profuse quantities of enzymes that act synergistically to degrade cellulase and related biomass components. We partially sequenced over 5100 random T. reesei cDNA clones. Among the sequences whose predicted gene products had significant similarity to known proteins, 12 were identified that encode previously unknown enzymes that likely function in biomass degradation. Microarrays were used to query the expression levels of each of the sequences under different conditions known to induce cellulolytic enzyme synthesis. Most of the genes encoding known and putative biomass-degrading enzymes were transcriptionally coregulated. Moreover, despite the fact that several of these enzymes are not thought to degrade cellulase directly, they were coordinately overexpressed in a cellulase overproducing strain. A variety of additional sequences whose function could not be ascribed using the limited sequence available displayed analogous behavior and may also play a role in biomass degradation or in the synthesis of biomass-degrading enzymes. Sequences exhibiting additional regulatory patterns were observed that might reflect roles in regulation of cellulase biosynthesis. However, genes whose products are involved in protein processing and secretion were not highly regulated during cellulase induction.

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Three α‐Galactosidase Genes of Trichoderma reesei Cloned by Expression in Yeast

Cited by 91 publications

References 47 publications

Crystal Structure of a Family 54 α-l-Arabinofuranosidase Reveals a Novel Carbohydrate-binding Module That Can Bind Arabinose

Crystal Structure of a Family 54 α-l-Arabinofuranosidase Reveals a Novel Carbohydrate-binding Module That Can Bind Arabinose

Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicola Strain BA

Transcriptional Regulation of Biomass-degrading Enzymes in the Filamentous Fungus Trichoderma reesei

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