Cloning, Sequencing, and Characterization of Two Clustered Cellulase-Encoding Genes, celS1 and celS2, from Streptomyces viridosporus T7A and their Expression in Escherichia coli.

Ramachandran, Suganthi S.; Magnuson, Timothy S.; Crawford, Don L.

doi:10.3209/saj.14_11

Cited by 3 publications

(1 citation statement)

References 23 publications

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“…Indeed, several bacteria that are able to degrade crystalline cellulose contain multiple CBM33 proteins 13,14 and some of these are known to be coregulated with cellulases. 15,16 Proteins classified as glycoside hydrolase family 61 (GH61) are structurally similar to CBM33 17,18 and are known to act synergistically with cellulases. However, the potentiating mechanism of these proteins remains enigmatic and activity has so far only been shown for rather complex substrates, that is, not for pure cellulose.…”

Section: Introductionmentioning

confidence: 99%

Cleavage of cellulose by a CBM33 protein

et al. 2011

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Bacterial proteins categorized as family 33 carbohydrate-binding modules (CBM33) were recently shown to cleave crystalline chitin, using a mechanism that involves hydrolysis and oxidation. We show here that some members of the CBM33 family cleave crystalline cellulose as demonstrated by chromatographic and mass spectrometric analyses of soluble products released from Avicel or filter paper on incubation with CelS2, a CBM33-containing protein from Streptomyces coelicolor A3(2). These enzymes act synergistically with cellulases and may thus become important tools for efficient conversion of lignocellulosic biomass. Fungal proteins classified as glycoside hydrolase family 61 that are known to act synergistically with cellulases are likely to use a similar mechanism.

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Section: Introductionmentioning

confidence: 99%

Cleavage of cellulose by a CBM33 protein

et al. 2011

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A Single Target Is Sufficient To Account for the Biological Effects of the A-Factor Receptor Protein ofStreptomyces griseus

et al. 2004

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In the model of the A-factor (2-isocapryloyl-3R-hydroxymethyl-␥-butyrolactone) regulatory cascade in Streptomyces griseus, A-factor binds ArpA, the A-factor receptor protein, that has bound to the adpA promoter and dissociates it from the DNA, thus inducing the transcription of adpA. AdpA switches on the transcription of a number of genes required for secondary metabolism and morphological differentiation, forming an AdpA regulon. Consistent with this model, arpA null mutants produced streptomycin and a yellow pigment in larger amounts and formed aerial hyphae from an earlier growth stage than the wild-type strain. On the other hand, mutant MK2, expressing a mutant ArpA (Trp119Ala), neither produced secondary metabolites nor formed aerial hyphae, because this A-factor-insensitive mutant ArpA always bound to and repressed the adpA promoter due to the amino acid replacement of Trp-119 with Ala. Introduction of adpA under the control of a foreign promoter into mutant MK2 restored all of the phenotypes that we could observe, which suggests that the only significant target of ArpA is adpA. In contrast to other ␥-butyrolactone regulatory systems, disruption of arpA had no effect on A-factor production, indicating that ArpA does not regulate A-factor biosynthesis. Instead, A-factor production was found to be repressed by AdpA in a two-step regulatory feedback loop.

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Transcriptional Control by A-Factor of Two Trypsin Genes in Streptomyces griseus

et al. 2005

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AdpA is the key transcriptional activator for a number of genes of various functions in the A-factor regulatory cascade in Streptomyces griseus, forming an AdpA regulon. Trypsin-like activity was detected at a late stage of growth in the wild-type strain but not in an A-factor-deficient mutant. Consistent with these observations, two trypsin genes, sprT and sprU, in S. griseus were found to be members of the AdpA regulon; AdpA activated the transcription of both genes by binding to the operators located at about ؊50 nucleotide positions with respect to the transcriptional start point. The transcription of sprT and sprU, induced by AdpA, was most active at the onset of sporulation. Most trypsin activity exerted by S. griseus was attributed to SprT, because trypsin activity in an sprT-disrupted mutant was greatly reduced but that in an sprU-disrupted mutant was only slightly reduced. This was consistent with the observation that the amount of the sprT mRNA was much greater than that of the sprU transcript. Disruption of both sprT and sprU (mutant ⌬sprTU) reduced trypsin activity to almost zero, indicating that no trypsin genes other than these two were present in S. griseus. Even the double mutant ⌬sprTU grew normally and developed aerial hyphae and spores over the same time course as the wild-type strain.

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Cloning, Sequencing, and Characterization of Two Clustered Cellulase-Encoding Genes, celS1 and celS2, from Streptomyces viridosporus T7A and their Expression in Escherichia coli.

Cited by 3 publications

References 23 publications

Cleavage of cellulose by a CBM33 protein

Cleavage of cellulose by a CBM33 protein

A Single Target Is Sufficient To Account for the Biological Effects of the A-Factor Receptor Protein ofStreptomyces griseus

Transcriptional Control by A-Factor of Two Trypsin Genes in Streptomyces griseus

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