Molecular structure and rheological properties of short-side-chain heavily glycosylated porcine stomach mucin.
Molecular structure and rheological properties of short-side-chain heavily glycosylated porcine stomach mucin.
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DOI：
10.1021/bm700607w
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发表时间：
2007-10
影响因子：
6.2
通讯作者：
G. Yakubov;A. Papagiannopoulos;E. Rat;R. Easton;T. Waigh
中科院分区：
文献类型：
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作者：
G. Yakubov;A. Papagiannopoulos;E. Rat;R. Easton;T. Waigh
目前公认的MUC家族高分子量胃粘蛋白的模型是它们在本体溶液中采用多分散螺旋构象。我们开发了这个模型，使用良好的特点，高度纯化的猪胃粘蛋白Orthana是遗传上接近人类MUC 6型。它具有短侧链和低水平的唾液酸残基，并包含微量的半胱氨酸残基，如果含量丰富，则可能导致粘蛋白的自聚合。我们已经确定，粘蛋白的结构在散装解决方案对应于一个菊花链无规卷曲。动态光散射实验探测内部动态的球状亚基（个别雏菊）在约9 nm的长度尺度，而粘度和光散射测量表明，整个粘蛋白链的大小要大得多，约50 nm。体积粘度（η）以与短侧链合成梳形聚电解质相似的方式与粘蛋白浓度（c）成比例，并且其特征在于半稀态（η约为c1/2）和缠结态（η约为c3/2）之间的过渡。
The current accepted model for high-molecular-weight gastric mucins of the MUC family is that they adopt a polydisperse coil conformation in bulk solutions. We develop this model using well-characterized highly purified porcine gastric mucin Orthana that is genetically close to the human MUC6 type. It has short side chains and low levels of sialic acid residues and includes minute amounts of cysteine residues that, if abundant, can be responsible for the self-polymerization of mucin. We have established that the mucin structure in bulk solutions corresponds to a daisy-chain random coil. Dynamic light scattering experiments probe the internal dynamics of globular subunits (individual daisies) at the approximately 9 nm length scale, whereas viscosity and light scattering measurements indicate that the size of the whole mucin chains is much larger, approximately 50 nm. The bulk viscosity (eta) scales with mucin concentration (c) in a manner similar to that found for short-side-chain synthetic comb polyelectrolytes and is characterized by a transition between semidilute (eta approximately c1/2) and entangled (eta approximately c3/2) regimes.