Centre National de la Recherche Scientifique, Université Pierre et Marie Curie-Paris 6, Unité Mixte de Recherche 7139 Marine Plants and Biomolecules, Station Biologique, 29682, Roscoff Cedex, France.
Mar Biotechnol (NY). 2013 Jun;15(3):265-74. doi: 10.1007/s10126-012-9483-y. Epub 2012 Sep 26.
Carrageenans are sulfated polysaccharides that are found in the cell walls of red algae. These polysaccharides have gelling and texturizing properties that are widely appreciated in industrial applications. However, these functional properties depend strongly on the sulfation of the moieties of the carrabiose repetition unit. Here we aimed to monitor the sulfate composition of gelling carrageenan. To do so, we screened and purified from Pseudoalteromonas atlantica a 4S-iota carrageenan sulfatase that converts ι-carrabiose into α-carrabiose units. The sequence of this protein matched the annotated Q15XH3 (Uniprot databank) formylglycine-dependent sulfatase found in the P. atlantica genome. With pure enzyme, ι-carrageenan could be transformed into a hybrid ι-/α-carrageenan or pure α-carrageenan. Analysis of the distribution of the carrabiose moieties in hybrid carrageenan chain using enzymatic degradation with Alteromonas fortis ι-carrageenase, coupled with chromatography and NMR spectroscopy experiments, showed that the sulfatase has an endo mode of action. The endo-character and the specificity of the sulfatase made it possible to prepare hybrid κ-/ι-/α-carrageenan and κ-/α-carrageenan starting from κ-/ι-carrageenan.
卡拉胶是一种存在于红藻细胞壁中的硫酸化多糖。这些多糖具有胶凝和质构化特性，在工业应用中得到了广泛的认可。然而，这些功能特性强烈依赖于卡拉胶重复单元的部分的硫酸化程度。在这里，我们旨在监测胶凝卡拉胶的硫酸化组成。为此，我们从假交替单胞菌中筛选和纯化了一种 4S-iota 卡拉胶硫酸酯酶，该酶将 ι-卡拉胶转化为α-卡拉胶单元。该蛋白质的序列与假交替单胞菌基因组中注释的 Q15XH3（Uniprot 数据库）甲酰甘氨酸依赖的硫酸酯酶形式相匹配。使用纯酶，ι-卡拉胶可以转化为混合 ι-/α-卡拉胶或纯α-卡拉胶。使用 Alteromonas fortis ι-卡拉胶酶对混合卡拉胶链中的卡拉胶单元进行酶促降解，结合色谱和 NMR 光谱实验，分析其分布情况，表明该硫酸酯酶具有内切酶的作用模式。该硫酸酯酶的内切酶特性和特异性使得可以从 κ-/ι-卡拉胶开始制备混合 κ-/ι-/α-卡拉胶和 κ-/α-卡拉胶。
