Quartz crystal microbalance investigation of the interaction of bacterial toxins with ganglioside containing solid supported membranes
Quartz crystal microbalance investigation of the interaction of bacterial toxins with ganglioside containing solid supported membranes
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DOI：
10.1007/s002490050079
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发表时间：
1997-01-01
影响因子：
2
通讯作者：
Galla, HJ
中科院分区：
文献类型：
--
作者：
Janshoff, A;Steinem, C;Galla, HJ
用石英晶体微天平研究了霍乱毒素、破伤风毒素和百日咳毒素与含神经节苷脂的固体支撑膜的结合。通过将磷脂囊泡融合在化学吸附在置于5 MHz AT切割石英晶体上的一个金电极上的辛基乙基醚的疏水单层上来制备双层。通过测量石英共振频率的变化来测试神经节苷脂G（M1）、G（M3）、G（D1 a）、G（D1 b）、G（T1 b）和无唾液酸-G（M1）作为不同毒素的合适受体的能力。为了获得每个配体-受体-对的结合常数，成功地将Langmuir等温线拟合到实验吸附等温线。霍乱毒素对G（M1）表现出高亲和力（K-a=1.8）。10（8）M（-1）），对去唾液酸-G（M1）的亲和力较低（K-a=1.0.10（7）M-1），对G（M3）无亲和力。破伤风毒素的C片段与含有神经节苷脂G（D1 a）、G（D1 b）和G（T1 b）的膜以相似的亲和力结合（K-a类似于10（6）M-1），而与G（M3）未观察到结合。百日咳毒素与含有神经节苷脂G（D1 a）的膜结合，结合常数为K-a = 1.6.10（6）M-1，但仅当存在大量（40 mol%）G（D1 a）时。由蛋白质吸附引起的最大频移强烈地依赖于受体的分子结构。这通过观察到破伤风毒素C片段吸附到G（D1 b）上的最大频率降低99 Hz而清楚地证明。与这种大的频率降低（相对于Sauerbrey方程出乎意料地高，意味着纯质量负载）相反，在破伤风毒素C片段吸附到G（D1 a）上后检测到仅28 Hz的最大偏移。
The binding of cholera toxin, tetanus toxin and pertussis toxin to ganglioside containing solid supported membranes has been investigated by quartz crystal microbalance measurements. The bilayers were prepared by fusion of phospholipid-vesicles on a hydrophobic monolayer of octanethiol chemisorbed on one gold electrode placed on the 5 MHz AT-cut quartz crystal. The ability of the gangliosides G(M1), G(M3), G(D1a), G(D1b), G(T1b) and asialo-G(M1) to act as suitable receptors for the different toxins was tested by measuring the changes of quartz resonance frequencies. To obtain the binding constants of each ligand-receptor-couple Langmuir-isotherms were successfully fitted to the experimental adsorption isotherms. Cholera toxin shows a high affinity for G(M1) (K-a=1.8 . 10(8)M(-1)), a lower one for asialo-G(M1) (K-a=1.0.10(7) M-1) and no affinity for G(M3). The C-fragment of tetanus toxin binds to ganglioside G(D1a), G(D1b) and G(T1b) containing membranes with similar affinity (K-a similar to 10(6) M-1), while no binding was observed with G(M3). Pertussis toxin binds to membranes containing the ganglioside G(D1a) with a binding constant of K-a = 1.6.10(6) M-1, but only if large amounts (40 mol%) of G(D1a) are present. The maximum frequency shift caused by the protein adsorption depends strongly on the molecular structure of the receptor. This is clearly demonstrated by an observed maximum frequency decrease of 99 Hz for the adsorption of the C-fragment of tetanus toxin to G(D1b) In contrast to this large frequency decrease, which was unexpectedly high with respect to Sauerbrey's equation, implying pure mass loading, a maximum shift of only 28 Hz was detected after adsorption of the C-fragment of tetanus toxin to G(D1a).