Alignment of fibrillin molecules in elastic microfibrils is defined by transglutaminase-derived cross-links.
Alignment of fibrillin molecules in elastic microfibrils is defined by transglutaminase-derived cross-links.
复制标题
弹性微原纤维中原纤维蛋白分子的排列是由转谷氨酰胺酶衍生的交联决定的。
作者：
R. Qian;R. Glanville
以珠状细丝的形式从人羊膜中提取微纤维，并使用丙烯腈衍生法分析转谷氨酰胺酶衍生的交联物的存在。从珠状细丝的蛋白酶水解物中分离得到该交联结构，并与标准品进行比较，鉴定为苯硫代氨基甲酰氨基酸衍生物。分离的交联物酸解得到预期的赖氨酸和谷氨酸，比例为1：1。珠状细丝还被胰酶处理，以产生包含珠状结构的部分和包含珠间细丝片段的部分。在珠间细丝中检测到了交联剂，但在珠子中未检测到。分离并测序了一个含有交联物的大分子胰蛋白酶多肽。获得的两个氨基酸序列证实了这两个交联分子都是纤维蛋白-1，并使分子内交联点的大致定位成为可能。两个相邻分子上的交联点的位置固定了纤维蛋白单体在微纤维中的相对位置，从而提供了对纤维蛋白在弹性微纤维中的空间组织的洞察。
Microfibrils were extracted from human amnion in the form of a beaded filament and analyzed for the presence of transglutaminase-derived cross-links using acrylonitrile derivatization. The cross-link structure was isolated from protease hydrolysates of beaded filaments and identified as a phenylthiocarbamyl amino acid derivative by comparison to a standard. Acid hydrolysis of the isolated cross-link gave the expected lysine and glutamic acid in a 1:1 ratio. The beaded filaments were also treated with trypsin to produce a fraction that contained the bead structure and a fraction containing fragments of the interbead filaments. Cross-links were detected in the interbead filaments but not in the beads. A large tryptic peptide that contained a cross-link was isolated and sequenced. The two amino acid sequences obtained identified both of the cross-linked molecules as fibrillin-1 and enabled the approximate localization of the cross-link sites within the molecule. The locations of cross-link sites on two adjacent molecules fixed the relative positions of fibrillin monomers within the microfibrils, providing insight into the spatial organization of fibrillin within the elastic microfibrils.