ATP-enhanced molecular chaperone functions of the small heat shock protein human alphaB crystallin.
ATP-enhanced molecular chaperone functions of the small heat shock protein human alphaB crystallin.
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DOI：
10.1073/pnas.95.3.1004
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发表时间：
1998-02
影响因子：
11.1
通讯作者：
P. Muchowski;J. Clark
中科院分区：
文献类型：
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作者：
P. Muchowski;J. Clark
我们报道了直接的实验证据，人α-晶体蛋白是小分子热休克蛋白家族的成员，在体外积极参与柠檬酸合成酶(CS)的复性。在3.5 mM的三磷酸腺苷存在下，α-晶状体蛋白对CS的再激活作用增强了近两倍。同样，3.5 mM的ATP增强了α-晶体蛋白在45℃下CS展开和聚集过程中的伴侣活性。与这些发现一致，在表达α-晶体蛋白的大肠杆菌中，50℃下的细胞活力提高了近5个数量级。对细胞裂解产物的SDS/PAGE分析表明，α-晶状体蛋白通过保持胞浆蛋白的天然和功能构象来保护细胞免受体内生理应激的影响。本报告证实了α-晶体蛋白在体内外作为分子伴侣的作用，并描述了三磷酸腺苷对α-晶体蛋白伴侣功能的增强作用。
We report direct experimental evidence that human alphaB-crystallin, a member of the small heat shock protein family, actively participates in the refolding of citrate synthase (CS) in vitro. In the presence of 3.5 mM ATP, CS reactivation by alphaB-crystallin was enhanced approximately twofold. Similarly, 3.5 mM ATP enhanced the chaperone activity of alphaB-crystallin on the unfolding and aggregation of CS at 45 degrees C. Consistent with these findings, cell viability at 50 degrees C was improved nearly five orders of magnitude in Escherichia coli expressing alphaB-crystallin. SDS/PAGE analysis of cell lysates suggested that alphaB-crystallin protects cells against physiological stress in vivo by maintaining cytosolic proteins in their native and functional conformations. This report confirms the action of alphaB-crystallin as a molecular chaperone both in vitro and in vivo and describes the enhancement of alphaB-crystallin chaperone functions by ATP.