In vitro disassembly and reassembly of an ABC transporter, the histidine permease
In vitro disassembly and reassembly of an ABC transporter, the histidine permease
复制标题
DOI：
10.1073/pnas.95.7.3495
复制
发表时间：
1998-03-31
影响因子：
11.1
通讯作者：
Ames, GFL
中科院分区：
文献类型：
--
作者：
Liu, PQ;Ames, GFL
鼠伤寒沙门氏菌周质组氨酸通透酶的膜结合复合物，是ABC转运蛋白（或交通ATP酶）超家族的一个成员;由两个整合膜蛋白HisQ和HisM以及两个拷贝的ATP结合亚基HisP组成。该复合物在由配体可溶性受体、周质组氨酸结合蛋白HisJ诱导活性时水解ATP。在此，我们利用该系统的模块化组织来表明核苷酸结合组分可以从完整的膜组分HisQ和HisM剥离。该复合物可以通过使用含有HisQ和HisM的HisP耗尽的膜和纯可溶性HisP来重构，我们表明HisP对HisP耗尽的复合物HisQM具有高亲和力，并且对于每个HisQM单元，两个HisP分子彼此独立地被募集。体外重新组装的复合物具有完全正常的性质，对HisJ和ATP酶抑制剂的响应具有与原始复合物相同的特性，并且与可溶性HisP的特性相反，这些结果表明HisP是ATP水解所必需的，HisQM不能水解ATP，HisP依赖于HisQM来传递来自可溶性受体HisJ的诱导信号，HisQM调节HisP的ATP酶活性。我们还表明，HisP在暴露于磷脂时会改变构象。
The membrane-bound complex of the Salmonella typhimurium periplasmic histidine permease, a member of the ABC transporters (or traffic ATPases) superfamily; is composed of two Integral membrane proteins, HisQ and HisM, and two copies of an ATP-binding subunit, HisP. The complex hydrolyzes ATP upon induction of the activity by the liganded soluble receptor, the periplasmic histidine-binding protein, HisJ, Here we take advantage of the modular organization of this system to show that the nucleotide-binding component can be stripped off the integral membrane components, HisQ and HisM, The complex can be reconstituted by using the HisP-depleted membranes containing HisQ and HisM and pure soluble HisP, We show that HisP has high affinity for the HisP-depleted complex, HisQM, and that two HisP molecules are recruited independently of each other for each HisQM unit, The in vitro reassembled complex has entirely normal properties, responding to HisJ and ATPase inhibitors with the same characteristics as the original complex and in contrast to those of soluble HisP, These results show that HisP is absolutely required for ATP hydrolysis, that HisQM cannot hydrolyze ATP, that HisP depends on HisQM to relay the inducing signal from the soluble receptor, HisJ, and that HisQM regulates the ATPase activity of HisP, We also show that HisP changes conformation upon exposure to phospholipids.