Expression and native structure of cytosolic class II small heat-shock proteins
Expression and native structure of cytosolic class II small heat-shock proteins
复制标题
DOI：
10.1104/pp.114.4.1477
复制
发表时间：
1997-08-01
期刊：
影响因子：
7.4
通讯作者：
Vierling, E
中科院分区：
文献类型：
--
作者：
Helm, KW;Lee, GJ;Vierling, E
高等植物合成小分子热激蛋白（smHSPs）来自五个相关基因家族。I类和II类家族编码胞质smHSP。我们的特点是第二类smHSPs豌豆（豌豆），并比较它们与第一类smHSPs。针对重组HSP17.7（一种II类smHSP）的抗体识别四种热诱导的17至18 kD多肽，并且不与I类smHSP交叉反应。在蔗糖梯度的II类smHSP沉积主要在8 Svedberg单位，表明它们是类似于I类smHSP复合物的大小的大复合物的组成部分。然而，I类和II类复合物很容易区分非变性聚丙烯酰胺凝胶电泳和等电聚焦。使用抗HSP 17.7或抗HSP 18.1（一种I类smHSP）抗血清的非变性免疫沉淀进一步证明I类和II类smHSP存在于不同的复合物中，主要由smHSP组成。重组HSP 17.7和HSP 18.1形成的复合物的大小与体内形成的复合物相似。当这两种smHSP混合，用尿素变性，然后透析时，再次形成不同的I类和II类复合物，每种复合物仅含有HSP 18.1或HSP 17.7。因此，同时表达的来自两个相关基因家族的胞质smHSP在体内形成不同的复合物，表明它们具有微妙的不同功能。
Higher plants synthesize small heat-shock proteins (smHSPs) from five related gene families. The class I and II families encode cytosolic smHSPs. We characterized the class II smHSPs of pea (Pisum sativum) and compared them with class I smHSPs. Antibodies against recombinant HSP17.7, a class II smHSP, recognized four heat-inducible 17- to 18-kD polypeptides and did not cross-react with class I smHSPs. On sucrose gradients the class II smHSPs sedimented primarily at 8 Svedberg units, indicating that they are components of large complexes similar in size to class I smHSP complexes. However, the class I and II complexes were readily distinguishable by nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing. Nondenaturing immune precipitations using anti-HSP17.7 or anti-HSP18.1 (a class I smHSP) antiserum provide further evidence that the class I and II smHSPs exist in different complexes, composed primarily of smHSPs. Recombinant HSP17.7 and HSP18.1 formed complexes of sizes similar to those formed in vivo. When these two smHSPs were mixed, denatured with urea, and then dialyzed, the distinct class I and II complexes again formed, each containing only HSP18.1 or HSP17.7. Thus, cytosolic smHSPs from two related gene families expressed simultaneously form distinct complexes in vivo, suggesting that they have subtly different functions.