Crystal structure of the petal death protein from carnation flower.
Crystal structure of the petal death protein from carnation flower.
复制标题
康乃馨花瓣死亡蛋白的晶体结构。
DOI：
10.1021/bi051779y
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Herzberg,Osnat
中科院分区：
文献类型：
--
作者：
Teplyakov,Alexey;Liu,Sijiu;Lu,Zhibing;Howard,Andrew;Dunaway-Mariano,Debra;Herzberg,Osnat
石竹（dianthus caryophyllus，石竹，三叶草粉）花瓣衰老过程中乙烯的产生诱导了PSR132蛋白的表达，因此该蛋白被命名为花瓣死亡蛋白（petal death protein， PDP）。最近的研究表明，尽管PDP在序列数据库中被注释为羧基磷酸烯醇丙酮酸突变酶，但该酶实际上是一种C - C键切割裂解酶，具有广泛的底物谱。在2.7 Å分辨率下测定了PDP的晶体结构，揭示了二聚体的低聚体缔合。与序列同源性一致，PDP的整体α/β桶折叠与其他异柠檬酸裂解酶/PEP突变酶超家族成员相同，包括在二聚体中交换的第8螺旋。此外，Mg2+结合在PDP的活性位点，其配位模式与其他超家族成员相似。与催化残基Cys144共价结合的化合物被解释为戊二醛交联晶体反应产生的硫代半缩醛加合物。携带cys144的柔性环进入活性位点，处于封闭构象。结合底物模型以及与异柠檬酸裂解酶和2-甲基异柠檬酸裂解酶的封闭构象的比较揭示了PDP广泛底物分布的结构基础。
Expression of the PSR132 protein fromDianthus caryophyllus(carnation, clover pink) is induced in response to ethylene production associated with petal senescence, and thus the protein is named petal death protein (PDP). Recent work has established that despite the annotation of PDP in sequence databases as carboxyphosphoenolpyruvate mutase, the enzyme is actually a C−C bond cleaving lyase exhibiting a broad substrate profile. The crystal structure of PDP has been determined at 2.7 Å resolution, revealing a dimer-of-dimers oligomeric association. Consistent with sequence homology, the overall α/β barrel fold of PDP is the same as that of other isocitrate lyase/PEP mutase superfamily members, including a swapped eighth helix within a dimer. Moreover, Mg2+binds in the active site of PDP with a coordination pattern similar to that seen in other superfamily members. A compound, covalently bound to the catalytic residue, Cys144, was interpreted as a thiohemiacetal adduct resulting from the reaction of glutaraldehyde used to cross-link the crystals. The Cys144-carrying flexible loop that gates access to the active site is in the closed conformation. Models of bound substrates and comparison with the closed conformation of isocitrate lyase and 2-methylisocitrate lyase revealed the structural basis for the broad substrate profile of PDP.