He Jinshan, Ochiai Akihito, Fukuda Yasuki, Hashimoto Wataru, Murata Kousaku
Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan.
FEMS Microbiol Lett. 2008 Nov;288(2):221-6. doi: 10.1111/j.1574-6968.2008.01354.x. Epub 2008 Sep 17.
Gram-negative Sphingomonas sp. strain A1 accumulates alginate in the cell surface pit and directly incorporates the polysaccharide into its cytoplasm through a 'superchannel'. A cell surface protein Algp7 (27 kDa) is inducibly expressed in the presence of alginate. Although the protein Algp7 was initially classified as a lipoprotein based on its primary structure, Algp7 purified from strain A1 cells did not possess a lipid moiety. Algp7 bound alginate efficiently at a neutral pH with a K(d) of 3.6 x 10(-8) M, suggesting that the cell surface protein contributed to accumulation of alginate in the pit.
革兰氏阴性鞘氨醇单胞菌属菌株A1在细胞表面凹陷处积累藻酸盐，并通过一个“超级通道”将这种多糖直接纳入其细胞质中。细胞表面蛋白Algp7（27 kDa）在藻酸盐存在时可诱导表达。尽管根据其一级结构，蛋白Algp7最初被归类为脂蛋白，但从菌株A1细胞中纯化得到的Algp7并不具有脂质部分。Algp7在中性pH条件下能有效地结合藻酸盐，解离常数K(d)为3.6×10(-8) M，这表明该细胞表面蛋白有助于藻酸盐在凹陷处的积累。
