Contribution of the HEDJ/ERdj3 cysteine-rich domain to substrate interactions
Contribution of the HEDJ/ERdj3 cysteine-rich domain to substrate interactions
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DOI：
10.1016/j.abb.2007.10.001
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发表时间：
2007-12-15
影响因子：
3.9
通讯作者：
Haslam, David B.
中科院分区：
文献类型：
--
作者：
Marcus, Nancy Y.;Marcus, Roland A.;Haslam, David B.
细胞质1型DnaJ/Hsp 40分子伴侣含有一个富含Cys的结构域，该结构域由四个CXXCXG基序组成，这些基序处于还原状态并与锌配位，从而稳定环结构中的间插序列。然而，内质网定位的HEDJ的富含Cys的区域（ERdj 3/ERj 3 p）在序列和排列上是相当不同的。与典型的I型分子不同，本研究证明HEDJ CXC和CXXC基序主要在分子内二硫键中氧化。在天然状态下，HEDJ与固定化的变性甲状腺球蛋白结合。与其结合伴侣GRP 78不同，氧化还原条件影响HEDJ与底物的相互作用。在体外试验中，用丝氨酸取代富含Cys的结构域半胱氨酸残基减少或消除了HEDJ结合。这些研究结果表明，HEDJ和其氧化态的Cys-丰富的区域是重要的，在保持底物相互作用域的结合能力的构象。(c)2007年爱思唯尔公司All rights reserved.
Cytoplasmic type 1 DnaJ/Hsp40 chaperones contain a Cys-rich domain consisting of four CXXCXG motifs that are in a reduced state and coordinate zinc, stabilizing the intervening sequence in a loop structure. However, the Cys-rich region of the endoplasmic reticulum localized HEDJ (ERdj3/ERj3p), is considerably different in sequence and arrangement. Unlike the typical type I molecule, the HEDJ CXC, and CXXC motifs were demonstrated in this study to be predominantly oxidized in intramolecular disulfide bonds. In the native state, HEDJ bound to immobilized, denatured thyroglobulin. Unlike its binding partner GRP78, redox conditions affected the interaction of HEDJ with substrate. Substitution of the Cys-rich domain cysteine residues with serine diminished or abolished HEDJ binding in the in vitro assay. These findings suggest that the Cys-rich region of HEDJ and its oxidation state are important in maintaining the substrate interaction domain in a binding-competent conformation. (c) 2007 Elsevier Inc. All rights reserved.