The main products of hydrolysis are iota-neocarratetraose sulfate and iota-neocarrahexaose sulfate. iota-Neocarraoctaose is the shortest substrate oligomer that can be cleaved. Unlike EC 3.2.1.81, beta-agarase and EC 3.2.1.83, kappa-carrageenase, this enzyme proceeds with inversion of the anomeric configuration. iota-Carrageenan differs from kappa-carrageenan by possessing a sulfo group on O-2 of the 3,6-anhydro-D-galactose residues, in addition to that present in the kappa-compound on O-4 of the D-galactose residues.
the enzyme belongs to glycohydrolase family 82, GH82, forming a deeply branched cluster in the phylogenetic tree, along with Celly_2571 and CgiA3, distinct from other iota-carrageenases; the enzyme belongs to the glycosyl hydrolase family 82, GH82
the enzyme belongs to glycohydrolase family 82, GH82, forming a deeply branched cluster in the phylogenetic tree, along with Celly_2571 and CgiA3, distinct from other iota-carrageenases; the enzyme belongs to the glycosyl hydrolase family 82, GH82
the smallest hybrid is an octasaccharide with a iota-iota-nu-iota structure, the second fraction is composed of two decasaccharides with iota-iota-iota-nu-iota and iota-[iota/nu]iota-iota structures, the third fraction is a mixture of dodecasaccharides which contains at least a iota-iota-iota-iota-nu-iota oligosaccharide
from an open conformation which allows the initial endo-attack of iota-carrageenan chains, the enzyme switches to a closed-tunnel form, consistent with its highly processive character
hybrid kappa/iota-carrageeans extracted from Gigartina skottsbergii, Chondracanthus chamissoi, and Chondrus crispus are incubated with Pseudoalteromonas carrageenovora kappa-carrageenase and Alteromonas fortis iota-carrageenase. A low percentage of degradation is observed after treatment by iota-carrageenase, suggesting that long segments of iota-carrabiose or block of iota-carrageenan are low in abundance
the endo-type iota-carrageenase hydrolyzes beta-1,4-linkages of iota-carrageenan yielding neo-iota-carratetraose as the main product in the absence of NaCl, mass and NMR spectrometric product analysis, overview
the endo-type iota-carrageenase hydrolyzes beta-1,4-linkages of iota-carrageenan yielding neo-iota-carratetraose as the main product in the absence of NaCl, mass and NMR spectrometric product analysis, overview
the enzyme requires the Na+ ion for full activity, maximal activity is observed in the presence of 0.1 M NaCl. In buffer containing 10 mM NaCl, the enzyme activity decreases to 28% during 16 h incubation on ice
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Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
concentration to 6 mg/ml using a dialyzing concentrator. The structure of iota-carrageenase bound to iota-carrageenan fragments is solved at 2.0 A resolution
hanging-drop vapour-diffusion method using polyethylene glycol (MW = 6000) as a precipitant. Crystals belong to space group P2(1), with unit-cell parameters a = 56.75 A, b = 91.04 A, c = 125.01 A, beta = 93.4°. The unit cell contains two molecules in the asymmetric unit related by a non-crystallographic twofold axis. Crystals diffracted to 2.0 A resolution on a synchrotron beamline
native and selenomethionyl-iota-carrageenase. Single crystals are obtained with polyethylene glycol, and the presence of Ca2+ appears to be crucial for crystallization. High quality crystals, typically 0.25 * 0.25 * 0.15 mM in dimension are grown with 0.1 M sodium cacodylate at pH 6.5, 15-17% polyethylene glycol and 200 mM calcium acetate. Crystallization of Se-Met-iota-carrageenase is performed under similar conditions except for the addition of 1 mM dithiothreitol and the replacement of sodium cacodylate by imidazole to avoid the reaction between cacodylate and dithiothreitol. Crystal structure at 1.6 A resolution
the enzyme is stable up to 45°C in 50 mM Tris/HCl, pH 7.5, containing 0.1 M NaCl and 1 mM CaCl2 for 1 h. Incubation at 45°C inactivates the enzyme completely within 5 min at either condition of low NaCl concentration (less than 10 mM) or presence of 10 mM EDTA
gene cgiB_Ce, DNA and amino acid sequence determination and analysis, phylogenetic analysis, recombinant expression in Escherichia coli strain BL21(DE3); gene cgiB_Ce, DNA and amino acid sequence determination and analysis, phylogenetic analysis, recombinant expression of His-tagged enzyme in Escherichia coli strain BL21(DE3)
gene encoding iota-carrageenase flanked by a C-terminal hexahistidine tag and a N-terminal PelB signal peptide for targeting the gene product into Escherichia coli periplasm. The recombinant plasmid, referred to as pETIAf, is used to transform Escherichia coli BL21(DE3) strain harbouring pLysS plasmid
the Km value is reduced by a factor of about 4, the reduction in kcat by 50fold results in a substantial decrease in the overall enzyme efficiency (about 10fold)
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APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
analysis
Alteromonas fortis
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usage of the enzyme for the analysis of the distribution of the carrabiose moieties in hybrid carrageenan chains, hybrid iota-/alpha-carrageenan, by Pseudoalteromonas atlantica a 4S-iota carrageenan sulfatase that converts iota-carrabiose into alapha-carrabiose units
In vitro release by Aspergillus fumigatus of galactofuranose antigens, 1,3-beta-D-glucan, and DNA, surrogate markers used for diagnosis of invasive aspergillosis
Hyper-production and characterization of the iota-carrageenase useful for iota-carrageenan oligosaccharide production from a deep-sea bacterium, Microbulbifer thermotolerans JAMB-A94T, and insight into the unusual catalytic mechanism