Concentrated solutions of salivary MUC5B mucin do not replicate the gel-forming properties of saliva
Concentrated solutions of salivary MUC5B mucin do not replicate the gel-forming properties of saliva
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DOI：
10.1042/0264-6021:3620289
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发表时间：
2002-03-01
影响因子：
4.1
通讯作者：
Sheehan, JK
中科院分区：
文献类型：
--
作者：
Raynal, BDE;Hardingham, TE;Sheehan, JK
我们已经开发了一种新的方法来研究唾液粘液和唾液粘蛋白的分子组织使用共聚焦荧光光漂白后恢复（共聚焦-FRAP）。从唾液中制备MUC 5 B粘蛋白、其还原亚基和T结构域并进行荧光标记。通过共焦FRAP确定平移自扩散系数高达3.6 mg/ml。结果表明，在纯化的MUC 5 B粘蛋白的溶液中，在流体动力学结构域重叠的浓度下，分子间的相互作用主要是由于动态缠结，并且没有证据表明MUC 5 B粘蛋白或其亚基或T-结构域的特异性自缔合。唾液粘液凝胶的分析也显示与纯化的MUC 5 B组分没有特异性相互作用，但其渗透性比从其MUC 5 B含量预期的低得多。唾液是完全可渗透的微球的直径为207 nm，但显示出尺寸依赖性的影响较大的微球（499 nm和711 nm直径）的扩散。从这些分析中，唾液粘液被证明是渗透性和动态的，并且具有在生理浓度下的半稀释瞬态网络的特征。唾液和纯化的MUC 5 B粘蛋白溶液的结果的比较表明，唾液的网络性质相当于高10-20倍浓度的纯化的MUC 5 B粘蛋白溶液。这表明唾液具有纯化的MUC 5 B粘蛋白中不存在的额外结构和组织，并表明唾液中存在与MUC 5 B联合收割机组合以产生其完整性质的其他相互作用和/或组分。
We have developed a new approach to study the molecular organization of salivary mucus and salivary mucins using confocal fluorescence recovery after photobleaching (confocal-FRAP). MUC5B mucin, its reduced subunit and T-domains were prepared from saliva and fluorescently labelled. The translational self-diffusion coefficients were determined up to 3.6 mg/ml by confocal-FRAP. The results suggest that, in solutions of purified MUC5B mucin, at concentrations at which the hydrodynamic domains overlap, the intermolecular interactions are predominantly due to dynamic entanglements, and there was no evidence of specific self-association of MUC5B mucin, or of its subunits, or T-domains. The analysis of the salivary mucus gel also showed no specific interactions with the purified MUC5B components, but it was much less permeable than expected from its MUC5B content. The saliva was completely permeable to microspheres of 207 nm diameter, but showed size-dependent effects on the diffusion of larger microspheres (499 nm and 711 nm diameter). From these analyses the salivary mucus was shown to be both permeable and dynamic, and with the characteristics of a semi-dilute transient network at physiological concentration. Comparison of the results from saliva and purified MUC5B mucin solutions showed that the network properties of saliva were equivalent to a solution of purified MUC5B mucin of 10-20 times higher concentration. This showed that saliva has additional structure and organization not present in the purified MUC5B mucin and suggests there are other interactions and/or components within saliva that combine with MUC5B to produce its complete properties.