Hardy S P, Lund T, Granum P E
School of Pharmacy and Biomolecular Sciences, University of Brighton, East Sussex, UK.
FEMS Microbiol Lett. 2001 Apr 1;197(1):47-51. doi: 10.1111/j.1574-6968.2001.tb10581.x.
CytK is a cytotoxin isolated from a strain of Bacillus cereus cultured from cases of necrotic enteritis and the amino acid sequence of the protein suggests that it may belong to the family of beta-barrel pore-forming toxins. We show here in planar lipid bilayers the toxin is able to form pores which are weakly anion selective and exhibit an open channel probability close to one. The predicted minimum pore diameter is approximately 7 A. We also show that cytK is a potent cytotoxin against human intestinal Caco-2 epithelia. CytK, like other beta-barrel pore-forming toxins, spontaneously forms oligomers which are resistant to sodium dodecyl sulphate (SDS), but not to boiling. CytK represents a pore-forming toxin linked with human cases of necrotic enteritis.
细胞毒素K（CytK）是从坏死性肠炎病例中培养的一株蜡样芽孢杆菌分离出的一种细胞毒素，该蛋白质的氨基酸序列表明它可能属于β-桶状成孔毒素家族。我们在此展示，在平面脂质双分子层中，该毒素能够形成具有弱阴离子选择性且开放通道概率接近1的孔。预测的最小孔径约为7埃。我们还表明，CytK是一种针对人肠道Caco-2上皮细胞的强效细胞毒素。与其他β-桶状成孔毒素一样，CytK能自发形成对十二烷基硫酸钠（SDS）有抗性但对煮沸敏感的寡聚体。CytK代表一种与人类坏死性肠炎病例相关的成孔毒素。
