INCREASED BODY-TEMPERATURE ACCELERATES AGGREGATION OF THE LEU-68 -] GLN MUTANT CYSTATIN-C, THE AMYLOID-FORMING PROTEIN IN HEREDITARY CYSTATIN-C AMYLOID ANGIOPATHY
INCREASED BODY-TEMPERATURE ACCELERATES AGGREGATION OF THE LEU-68 -] GLN MUTANT CYSTATIN-C, THE AMYLOID-FORMING PROTEIN IN HEREDITARY CYSTATIN-C AMYLOID ANGIOPATHY
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DOI：
10.1073/pnas.91.4.1416
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发表时间：
1994-02-15
影响因子：
11.1
通讯作者：
GRUBB, A
中科院分区：
文献类型：
--
作者：
ABRAHAMSON, M;GRUBB, A
遗传性胱抑素C淀粉样血管病是一种显性遗传性疾病，以痴呆、瘫痪和在成年早期死于脑出血为特征。半胱氨酸蛋白酶抑制剂的变体半胱氨酸蛋白酶抑制剂C在患者的组织中沉积为淀粉样蛋白，并且他们的脊髓液半胱氨酸蛋白酶抑制剂C水平异常低。疾病相关的Leu-68 --> Gln突变体（L 68 Q）胱抑素C已在大肠杆菌表达系统中产生，并通过使用变性缓冲液、免疫吸附和凝胶过滤分离。L 68 Q-半胱氨酸蛋白酶抑制剂C和野生型半胱氨酸蛋白酶抑制剂C的平行物理化学和功能研究显示，这两种蛋白质有效地抑制半胱氨酸蛋白酶组织蛋白酶B（解离平衡常数，分别为0.4和0.5 nM），但在其二聚化和形成聚集体的趋势上有很大差异。虽然野生型半胱氨酸蛋白酶抑制剂C是单体的，即使在高温下长时间储存后也具有功能活性，但L 68 Q-半胱氨酸蛋白酶抑制剂C在转移到非变性缓冲液后立即开始二聚化并失去生物活性。L 68 Q半胱氨酸蛋白酶抑制剂C的二聚化是高度温度依赖性的，孵育温度从37 ° C升高至40 ° C导致二聚化速率增加150%。与37 ℃相比，生理浓度下的聚集同样在40 ℃下增加约60%。L 68 Q-胱抑素C的这些特性关系到我们对遗传性胱抑素C淀粉样血管病的病理生理过程的理解。它们也可能具有临床相关性，因为中止疾病性状携带者的发热期的医学干预可以减少L 68 Q-半胱氨酸蛋白酶抑制剂C聚集体的体内形成。
Hereditary cystatin C amyloid angiopathy is a dominantly inherited disorder, characterized by dementia, paralysis, and death from cerebral hemorrhage in early adult life. A variant of the cysteine proteinase inhibitor, cystatin C, is deposited as amyloid in the tissues of the patients and their spinal-fluid level of cystatin C is abnormally low. The disease-associated Leu-68 --> Gln mutant (L68Q) cystatin C has been produced in an Escherichia coli expression system and isolated by use of denaturing buffers, immunosorption, and gel filtration. Parallel physicochemical and functional investigations of L68Q-cystatin C and wild-type cystatin C revealed that both proteins effectively inhibit the cysteine proteinase cathepsin B (equilibrium constants for dissociation, 0.4 and 0.5 nM, respectively) but differ considerably in their tendency to dimerize and form aggregates. While wild-type cystatin C is monomeric and functionally active even after prolonged storage at elevated temperatures, L68Q-cystatin C starts to dimerize and lose biological activity immediately after it is transferred to a nondenaturing buffer. The dimerization of L68Q cystatin C is highly temperature-dependent, with a rise in incubation temperature from 37 to 40 degrees C resulting in a 150% increase in dimerization rate. The aggregation at physiological concentrations is likewise increased at 40 compared to 37 degrees C, by approximate to 60%. These properties of L68Q-cystatin C have bearing upon our understanding of the pathophysiological process of hereditary cystatin C amyloid angiopathy. They might also be of clinical relevance, since medical intervention to abort febrile periods of carriers of the disease trait may reduce the in vivo formation of L68Q-cystatin C aggregates.