Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701, Republic of Korea.
Plant Physiol Biochem. 2009 Oct;47(10):859-66. doi: 10.1016/j.plaphy.2009.06.008. Epub 2009 Jun 30.
Hsp90 proteins are essential molecular chaperones regulating multiple cellular processes in distinct subcellular organelles. In this study, we report the functional characterization of a cDNA encoding endoplasmic reticulum (ER)-resident Hsp90 from orchardgrass (DgHsp90). DgHsp90 is a 2742bp cDNA with an open reading frame predicted to encode an 808 amino acid protein. DgHsp90 has a well conserved N-terminal ATPase domain and a C-terminal Hsp90 domain and ER-retention motif. Expression of DgHsp90 increased during heat stress at 35 degrees C or H(2)O(2) treatment. DgHsp90 also functions as a chaperone protein by preventing thermal aggregation of malate dehydrogenase (EC 1.1.1.37) and citrate synthase (EC 2.3.3.1). The intrinsic ATPase activity of DgHsp90 was inhibited by geldanamycin, an Hsp90 inhibitor, and the inhibition reduced the chaperone activity of DgHsp90. Yeast cells overexpressing DgHsp90 exhibited enhanced thermotolerance.
Hsp90 蛋白是调节不同亚细胞细胞器中多种细胞过程的必需分子伴侣。在这项研究中，我们报告了一种来自草地早熟禾（DgHsp90）的内质网（ER）驻留 Hsp90 的 cDNA 的功能特征。DgHsp90 是一个 2742bp 的 cDNA，具有开放阅读框，预测编码一个 808 个氨基酸的蛋白质。DgHsp90 具有保守的 N 端 ATP 酶结构域和 C 端 Hsp90 结构域和 ER 保留基序。在 35°C 的热应激或 H2O2 处理期间，DgHsp90 的表达增加。DgHsp90 还作为伴侣蛋白发挥作用，防止苹果酸脱氢酶（EC 1.1.1.37）和柠檬酸合酶（EC 2.3.3.1）的热聚集。DgHsp90 的内在 ATP 酶活性被 geldanamycin 抑制，一种 Hsp90 抑制剂，抑制降低了 DgHsp90 的伴侣活性。过表达 DgHsp90 的酵母细胞表现出增强的耐热性。
