Specific conformational changes of plasminogen induced by chloride ions, 6-aminohexanoic acid and benzamidine, but not the overall openness of plasminogen regulate, production of biologically active angiostatins.
Specific conformational changes of plasminogen induced by chloride ions, 6-aminohexanoic acid and benzamidine, but not the overall openness of plasminogen regulate, production of biologically active angiostatins.
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由氯离子、6-氨基己酸和苯甲脒诱导的纤溶酶原的特定构象变化，但不是纤溶酶原的整体开放性，调节生物活性血管抑制素的产生。
DOI：
10.1042/bj20050907
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Twining,SallyS
中科院分区：
文献类型：
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作者：
Warejcka,DebraJ;Twining,SallyS
纤溶酶原的整体构象取决于阴离子和分子如AHA（6-氨基己酸）和BZ（苯甲脒）的存在。本研究的目的是确定构象对纤溶酶原的初始和二级裂解产生活性血管抑素的影响。纤溶酶原用生理学相关的中性粒细胞弹性蛋白酶在四种Tris/乙酸盐缓冲液之一中消化：单独的缓冲液或缓冲液加NaCl、AHA或BZ。Glu 1-纤溶酶原在NaCl诱导的α-紧构象中的起始裂解慢得多，在BZ诱导的中间β-构象中的起始裂解最快，在对照和AHA诱导的开放γ-构象中的起始裂解均为中间。尽管缓冲系统决定了初始裂解产物的相对量，但在所有条件下均使用相同的四个裂解位点。在BZ存在下观察到蛋白酶结构域内的第五个主要初始切割。血管抑制素形成所需的N-末端肽裂解作为初始裂解或次级裂解发生。在BZ存在下生成血管抑制素最快，在NaCl存在下生成最慢。初始和次级裂解都受到修饰剂的影响，表明它们影响Glu-纤溶酶原和初始裂解产物的构象。在不同条件下产生的血管抑素抑制人脐静脉内皮细胞的增殖。这些结果表明，纤溶酶原转化为活性血管抑制素更多地依赖于由各种修饰试剂诱导的特定构象变化，而不是分子的整体开放性。
The overall conformation of plasminogen depends upon the presence of anions and molecules such as AHA (6-aminohexanoic acid) and BZ (benzamidine). The purpose of the present study was to determine the effect of conformation on the initial and secondary cleavages of plasminogen to generate active angiostatins. Plasminogen was digested with the physiologically relevant neutrophil elastase in one of the four Tris/acetate buffers: buffer alone or buffer plus NaCl, AHA or BZ. The initial cleavage of Glu1-plasminogen was much slower in the tight NaCl-induced α-conformation, fastest in the intermediate BZ-induced β-conformation and intermediate both in the control and in the AHA-induced open γ-conformation. Although the buffer system determined the relative amounts of the initial cleavage products, the same four cleavage sites were utilized under all conditions. A fifth major initial cleavage within the protease domain was observed in the presence of BZ. N-terminal peptide cleavage required for angiostatin formation occurred as either the initial or the secondary cleavage. Angiostatins were generated fastest in the presence of BZ and slowest in the presence of NaCl. Both the initial and secondary cleavages were affected by the modifying agents, indicating that they influence the conformation of both Glu-plasminogen and the initial cleavage products. The angiostatins produced under the different conditions inhibited proliferation of human umbilical-vein endothelial cells. These results suggest that plasminogen conversion into active angiostatins is dependent more on the specific conformation changes induced by the various modifying reagents rather than on the overall openness of the molecule.