Dynamic interaction between chaperone and its substrates

伴侣蛋白将未折叠的蛋白质包裹在顺式空腔中，确保安全折叠而不必担心聚集。这个过程需要ATP水解的能量。目前的主要chaperonin函数模型假定只有一个病原chaperonin一步整个催化循环,也就是说,ATP水解需要8秒。然而,吉田和Funatsu〓年代小组提议,有两个速度限制步骤的循环,一个3秒,另5秒,这是基于单分子观察gro释放,ADP公布,蛋白质折叠发起的ATP只有3秒后开始滞后阶段。Kuwajima指出，构象变化是由ATP结合而不是ATP水解引起的。德田〓组在SecA系统中发现了新的因子SecG。与SecA类似，在蛋白质易位过程中，SecG在膜中翻滚。Kohno发现内质网应激传感器蛋白ire1 - β是一种切割28SrRNA的RNase。Gotoh成功地在酵母细胞中表达了人β -微球蛋白，并指出二硫键在淀粉样蛋白纤维的形成中起重要作用。吉田教授研究组开发出了能使单个淀粉样蛋白纤维生长的实时观察系统。结果表明，纤维以单向生长为主。

SummaryChaperonin encapsulates unfolded proteins in the cis cavity and ensures safe folding without fear of aggregation. This process requires the energy of ATP hydrolysis. Currently prevailing model of chaperonin function assumes only a single rate-limiting step in whole catalytic cycle of chaperonin, that is, ATP hydrolysis that needs 8 sec. However, Yoshida and Funatsu〓s group have proposed that there are two rate limiting steps in the cycle, one 3 sec and the other 5 sec. This is based on the single molecule observation that GroES release, ADP release, and protein folding initiated by addition of ATP only start after a 3-sec lag phase. Kuwajima showed the conformational change occurred by the ATP binding rather than ATP hydrolysis. Tokuda〓 group have found a new factor, SecG, in SecA system. Similar to SecA, during protein translocation, SecG tumbles in the membrane. Kohno identified that ER stress sensor protein, IRE1-beta, is an RNase that cleaves 28SrRNA. Gotoh succeeded in expression of human beta-microglobulin in yeast cells and pointed out that disulfide bond is important in formation of amyloid fibers. Yoshida〓s group has established a real-time observation system that allows the growth of single amyloid fiber. The result showed that fiber grew predominantly unnidirectionally.