| Production, Purification and Crystallization of a Prokaryotic SLC26 Homolog for Structural Studies
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Author:
Date:
2017-02-05
[Abstract] The SLC26 or SulP proteins constitute a large family of anion transporters that are ubiquitously expressed in pro- and eukaryotes. In human, SLC26 proteins perform important roles in ion homeostasis and malfunctioning of selected members is associated with diseases. This protocol details the production and crystallization of a prokaryotic SLC26 homolog, termed SLC26Dg, from Deinococcus geothermalis. Following these instructions we obtained well-folded and homogenous material of the membrane protein SLC26Dg and the nanobody Nb5776 that enabled us to crystallize the complex and determine its structure (Geertsma et al., 2015). The procedure may be adapted to purify and crystallize other membrane protein complexes.
[摘要] SLC26或SulP蛋白构成在亲和真核生物中普遍表达的大量阴离子转运蛋白。在人类中，SLC26蛋白在离子稳态中起重要作用，选择成员的功能障碍与疾病有关。该方案详细描述了来自地热异常球菌的原核SLC26同源物（称为SLC26Dg）的产生和结晶。按照这些说明，我们获得了膜蛋白SLC26Dg和纳米体Nb5776的良好折叠和均匀的材料，使我们能够使复合物结晶并确定其结构（Geertsma等人，2015）。该方法可以适于纯化和结晶其它膜蛋白复合物。
背景 除了少数例外，膜蛋白的结构表征涉及蛋白质生产水平，洗涤剂溶解状态下的稳定化和结晶的挑战。克服这些障碍所采取的策略取决于有效选择具有优异生物化学性质的SLC26同系物和使用抗体作为结晶伴侣（Geertsma等人，2015）。这里描述的程序并没有大大偏离同事的程序，但在几点上，我们采用其他方法。例如，对于蛋白质生产，我们利用araBAD启动子（Guzman等人，1995），而不是流行的T7启动子（Studier等人，1990）。与T7启动子相反，PAD启动子允许直接调节蛋白质生产水平及其对下游折叠机械的能力的调节，从而减少包涵体的形成（Geertsma， et ...
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| Analytical Gel Filtration for Probing Heavy Metal Transfer between Proteins
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Author:
Date:
2016-08-05
[Abstract] Heavy metals can cause damage to biomolecules such as proteins and DNA in multiple ways. Cells therefore strive for keeping intracellular (heavy) metal ions bound to specific proteins that are capable of handling detoxification, export or integration as cofactors. Metal binding proteins usually provide specific coordination sites that bind certain ions with ultrahigh affinity, with the thermodynamic driving force being the stability of organometallic complexes. However, the metal binding properties of these proteins can be highly variable. Therefore the transfer of specific ions between separate proteins or even between distinct binding sites located on one and the same protein does not always follow affinity gradients, but depends on particular protein interactions that are difficult to ...
[摘要] 重金属可以以多种方式对生物分子例如蛋白质和DNA造成损害。因此，细胞努力保持细胞内（重）金属离子结合到能够处理解毒，输出或整合作为辅因子的特定蛋白质。金属结合蛋白通常提供结合某些离子的特异性配位位点，具有超高的亲和力，热力学驱动力是有机金属配合物的稳定性。然而，这些蛋白质的金属结合性质可以是高度可变的。因此，在分开的蛋白质之间或甚至在位于同一蛋白质上的不同结合位点之间的特异性离子的转移不总是遵循亲和梯度，而是取决于难以预测的特定蛋白质相互作用。我们建立了一种适合探测两种蛋白质之间的金属转移的方法，只要这些蛋白质可以进行纯化和体外处理。它由金属负载，共孵育和金属交换蛋白的分离，随后确定结合金属含量。该方法通过我们探测膜 - 外在金属结合结构域MBD2和来自大肠杆菌的铜输出ATP酶的跨膜结构域的膜 - 外部金属结合结构域MBD2之间的铜（I）转移的实验数据来举例说明（Drees < em=""> 。，2015）。
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| Expression, Purification and Crystallization of the Herpesvirus Nuclear Egress Complex (NEC)
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Author:
Date:
2016-07-20
[Abstract] The protocol describes the production and crystallization of the soluble form of the nuclear egress complex (NEC) from Herpes simplex virus 1 and Pseudorabies virus. The NEC is a heterodimer that consists of conserved proteins UL31 and UL34. NEC oligomerization deforms the inner nuclear membrane around the capsid in infected cells, thereby mediating capsid budding into the perinuclear space during nuclear egress. We have successfully developed a protocol for large-scale preparation of highly pure NEC from two different viruses in a prokaryotic expression system, which enabled us to crystallize these viral protein complexes and determine their structures. This procedure may be adapted to purify and crystallize other soluble protein complexes.
[摘要] 该协议描述了来自单纯疱疹病毒1和伪狂犬病病毒的核出口复合物（NEC）的可溶形式的产生和结晶。 NEC是由保守蛋白UL31和UL34组成的异源二聚体。 NEC低聚使受感染细胞中的衣壳周围的内核膜变形，从而在核出口期间介导衣壳发芽进入核周空间。 我们已经成功地开发了一个协议，从大规模制备高纯度NEC从两种不同的病毒在原核表达系统，这使我们能够结晶这些病毒蛋白复合物和确定其结构。 该程序可适于纯化和结晶其它可溶性蛋白质复合物。
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