In vitro fibrillogenesis of collagen type I in varying ionic and pH conditions
In vitro fibrillogenesis of collagen type I in varying ionic and pH conditions
复制标题
DOI：
10.1016/j.micron.2013.03.004
复制
发表时间：
2013-06-01
期刊：
影响因子：
2.4
通讯作者：
Lewis, Richard J.
中科院分区：
文献类型：
--
作者：
Harris, J. Robin;Soliakov, Andrei;Lewis, Richard J.
胶原蛋白是人体中最丰富的蛋白质，在肌腱、软骨和骨骼的形成中起主要作用，它为皮肤提供机械强度，实际上几乎每个器官和肌肉都与一层胶原蛋白有关。因此，它是细胞外基质的关键成分。在这里，我们研究了在体外原纤维形成的乙酸可溶性胶原蛋白I型在生理和不同的非生理条件下，通过TEM从负染色标本。在pH 2.5时，胶原异源三聚体在增加的缓冲液浓度和增加的NaCl浓度的存在下保持可溶。在pH 4.5时，在低NaCl浓度下形成分子聚集体，但在较高NaCl浓度下形成具有类似于11 nm条带的扩散的原纤维。在pH 7.0时，在低NaCl浓度下形成初始分子聚集体，其逐渐形成类似于在中等NaCl浓度下的67 nm D-带胶原原纤维的特征，其在较高NaCl浓度下聚集形成较厚的多原纤维D-带纤维。相比之下，在pH 7.0下增加磷酸钠的浓度导致从最初的松散聚集形式的胶原蛋白在较高浓度下形成弯曲的、未带状的原纤维。在较高pH下，D带原纤维的形成效率较低，特别是在pH 9.0下。因此，在中性pH下，产生D-带胶原原纤维需要氯阴离子而不是钠阳离子的存在;在中性pH下，以NaCl或Tris-HCl形式的高于正常生理氯化物浓度的氯化物，而不是磷酸盐缓冲液，也可以导致D-带胶原原纤维的有效体外形成。(C)2013爱思唯尔有限公司保留所有权利。
Collagen is the most abundant protein in the human body, and has primary roles in the formation of tendons, cartilage and bone, it provides mechanical strength to skin and indeed almost every organ and muscle is associated with a layer of collagen. It is thus a key component of the extracellular matrix. Here we have studied the in vitro fibrillogenesis of acetic acid-soluble collagen type I under physiological and varying non-physiological conditions by TEM from negatively stained specimens. At pH 2.5 the collagen heterotrimer remains soluble at increasing buffer concentrations and in the presence of increasing NaCl concentrations. At pH 4.5 molecular aggregates form at low NaCl concentrations, but at higher NaCl concentrations fibrils with a diffuse similar to 11 nm banding are formed. At pH 7.0, initial molecular aggregates form at low NaCl concentrations that progressively form characteristic similar to 67 nm D-banded collagen fibrils at intermediate NaCl concentrations that cluster to form thicker multi-fibril D-banded fibres in higher NaCl concentrations. By contrast, increasing concentrations of sodium phosphate at pH 7.0 leads to the formation of flexuous, unbanded fibrils at higher concentrations from the initial, loosely aggregated form of collagen. At higher pHs, the formation of D-banded fibrils is less efficient, particularly at pH 9.0. Thus at neutral pH, the presence of chloride anions, rather than sodium cations, is required for the production of D-banded collagen fibrils; higher than normal physiological chloride concentrations in the form of NaCl or Tris-HCl at neutral pH, but not phosphate buffer, can also lead to the efficient in vitro formation of D-banded collagen fibrils. (C) 2013 Elsevier Ltd. All rights reserved.