Cellulose‐binding modules from extracellular matrix proteins of <i>Dictyostelium discoideum</i> stalk and sheath

Wang, Jenny; Slade, Martin B.; Gooley, Andrew A.; Atwell, Brian J.; Williams, Keith L.

doi:10.1046/j.1432-1327.2001.02354.x

Cited by 27 publications

(31 citation statements)

References 66 publications

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“…When conditions are sufficiently severe, the slug can form a fruiting body, where cells differentiate into a spore and stalk. During the formation of the slug and fruiting body, proteins and cellulose are deposited as an extracellular matrix, providing the organism with environmental protection and structural rigidity (1)(2)(3)(4). Cellulose is also found in the sheath that surrounds the cell aggregates and is deposited in the stalk, stalk cell walls, and spore coats (2,5).…”

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confidence: 99%

Biochemical and Structural Characterizations of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Level of Conservation between Distant Phylogenetic Trees of Life

Hobdey

Knott

Momeni

et al. 2016

Appl Environ Microbiol

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Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) are enzymes commonly employed in plant cell wall degradation across eukaryotic kingdoms of life, as they provide significant hydrolytic potential in cellulose turnover. To date, many fungal GH7 CBHs have been examined, yet many questions regarding structure-activity relationships in these important natural and commercial enzymes remain. Here, we present the crystal structures and a biochemical analysis of two GH7 CBHs from social amoeba: Dictyostelium discoideum Cel7A (DdiCel7A) and Dictyostelium purpureum Cel7A (DpuCel7A). DdiCel7A and DpuCel7A natively consist of a catalytic domain and do not exhibit a carbohydrate-binding module (CBM). The structures of DdiCel7A and DpuCel7A, resolved to 2.1 Å and 2.7 Å, respectively, are homologous to those of other GH7 CBHs with an enclosed active-site tunnel. Two primary differences between the Dictyostelium CBHs and the archetypal model GH7 CBH, Trichoderma reesei Cel7A (TreCel7A), occur near the hydrolytic active site and the product-binding sites. To compare the activities of these enzymes with the activity of TreCel7A, the family 1 TreCel7A CBM and linker were added to the C terminus of each of the Dictyostelium enzymes, creating DdiCel7A CBM and DpuCel7A CBM , which were recombinantly expressed in T. reesei. DdiCel7A CBM and DpuCel7A CBM hydrolyzed Avicel, pretreated corn stover, and phosphoric acid-swollen cellulose as efficiently as TreCel7A when hydrolysis was compared at their temperature optima. The K i of cellobiose was significantly higher for DdiCel7A CBM and DpuCel7A CBM than for TreCel7A: 205, 130, and 29 M, respectively. Taken together, the present study highlights the remarkable degree of conservation of the activity of these key natural and industrial enzymes across quite distant phylogenetic trees of life. IMPORTANCE GH7CBHs are among the most important cellulolytic enzymes both in nature and for emerging industrial applications for cellulose breakdown. Understanding the diversity of these key industrial enzymes is critical to engineering them for higher levels of activity and greater stability. The present work demonstrates that two GH7 CBHs from social amoeba are surprisingly quite similar in structure and activity to the canonical GH7 CBH from the model biomass-degrading fungus T. reesei when tested under equivalent conditions (with added CBM-linker domains) on an industrially relevant substrate. Dictyostelia are a class of social amoebae (historically known as slime molds) containing four different groups of terrestrial bacterivores from the kingdom Amoebozoa. During vegetative growth, dictyostelia exist as single-celled organisms; upon starvation, a lack of nutrients becomes preventive for vegetative growth and the cells aggregate into a multicellular slug. Slugs have a defined posterior and anterior, have the ability to migrate, are sensitive to light and temperature, and exhibit an innate immune system. When conditions are sufficiently severe, the slug can form a fruiting body, w...

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confidence: 99%

Biochemical and Structural Characterizations of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Level of Conservation between Distant Phylogenetic Trees of Life

Hobdey

Knott

Momeni

et al. 2016

Appl Environ Microbiol

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“…Some of the genes whose expression depends on gtaG and on Dd-STATa encode cellulose-binding proteins, and some of these proteins have been identified as extracellular matrix components of the slug sheath and the stalk (Wang et al, 2001). Interestingly, Loomis has proposed that culmination is caused by changes in sheath properties at the tip of the slug (Loomis, 2015).…”

Section: Discussionmentioning

confidence: 99%

The GATA transcription factor gene gtaG is required for terminal differentiation in Dictyostelium

Katoh-Kurasawa

Santhanam

Shaulsky

2016

Journal of Cell Science

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The GATA transcription factor GtaG is conserved in Dictyostelids and is essential for terminal differentiation in Dictyostelium discoideum, but its function is not well understood. Here, we show that gtaG is expressed in prestalk cells at the anterior region of fingers and in the extending stalk during culmination. The gtaG − phenotype is cellautonomous in prestalk cells and non-cell-autonomous in prespore cells. Transcriptome analyses reveal that GtaG regulates prestalk gene expression during cell differentiation before culmination and is required for progression into culmination. GtaG-dependent genes include genetic suppressors of the Dd-STATa-defective phenotype (Dd-STATa is also known as DstA) as well as Dd-STATa targetgenes, including extracellular matrix genes. We show that GtaG might be involved in the production of two culmination-signaling molecules, cyclic di-GMP (c-di-GMP) and the spore differentiation factor SDF-1, and that addition of c-di-GMP rescues the gtaG − culmination and spore formation deficiencies. We propose that GtaG is a regulator of terminal differentiation that functions in concert with Dd-STATa and controls culmination through regulating c-di-GMP and SDF-1 production in prestalk cells.

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“…OrfZ, however, consists of a module of unknown function (amino acids [aa] 1 to 104), a so-called PTS box (aa 105 to 175), and a cellulose binding module with high similarity to carbohydrate binding module type IIIb. This structure is unusual and hitherto found only in the eucaryotic slime mold Dictyostelium discoideum with a carbohydrate binding module, type IIa (22).…”

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confidence: 91%

Chi18A, the Endochitinase in the Cellulosome of the Thermophilic, Cellulolytic Bacterium Clostridium thermocellum

Zverlov

Fuchs

Schwarz

2002

Appl Environ Microbiol

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The chitinase gene chiA was identified on the Clostridium thermocellum genome downstream of the endoglucanase gene celA. It contains a catalytic module of glycosyl hydrolase family 18 and a cellulosomal dockerin module. Chi18A hydrolyzes aryl-acetyl-chito-oligosaccharides preferentially. In denaturing electrophoresis of purified cellulosomes, a single chitinase activity band was identified in zymograms and Western blots, indicating that Chi18A is the only chitinase in the cellulosome.

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Cellulose‐binding modules from extracellular matrix proteins of Dictyostelium discoideum stalk and sheath

Cited by 27 publications

References 66 publications

Biochemical and Structural Characterizations of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Level of Conservation between Distant Phylogenetic Trees of Life

Biochemical and Structural Characterizations of Two Dictyostelium Cellobiohydrolases from the Amoebozoa Kingdom Reveal a High Level of Conservation between Distant Phylogenetic Trees of Life

The GATA transcription factor gene gtaG is required for terminal differentiation in Dictyostelium

Chi18A, the Endochitinase in the Cellulosome of the Thermophilic, Cellulolytic Bacterium Clostridium thermocellum

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