Mechanism of Cu+-transporting ATPases:: Soluble Cu+ chaperones directly transfer Cu+ to transmembrane transport sites
Mechanism of Cu+-transporting ATPases:: Soluble Cu+ chaperones directly transfer Cu+ to transmembrane transport sites
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DOI：
10.1073/pnas.0711446105
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发表时间：
2008-04-22
影响因子：
11.1
通讯作者：
Argueello, Jose M.
中科院分区：
文献类型：
--
作者：
Gonzalez-Guerrero, Manuel;Argueello, Jose M.
与其他p型atp酶一样，Cu+- atp酶中金属与跨膜金属结合位点（TIMI-MBS）的结合是酶磷酸化和随后的转运所必需的。然而，Cu+不能以自由（水合）形式进入Cu+- atp酶，而是与伴侣蛋白结合。已经描述了Cu+从Cu+伴侣转移到这些atp酶中存在的调节细胞质金属结合域（MBDs），但没有证据表明随后Cu+从MBDs转移到TM-MIBS。或者，我们假设伴侣直接将Cu+转移到TM-MBS。通过对这两种模型的测试，研究了fulgidus Archaeoglobus Cu+伴侣CopZ对Cu+- atp酶CopA的传递。正如预期的那样，CopZ与金属交互并将其交付给CopA mbd。Cu+加载的mbd作为金属供体，不能激活CopA或缺乏mbd的截断CopA。相反，Cu+负载的CopZ激活了CopA ATIPase和CopA结构，使mbd无法结合Cu+。此外，在非周转条件下，CopZ将Cu+转移到缺乏MBDs的CopA的TM-MBS中。这些数据与mbd在不参与金属运输的情况下发挥调节功能的模型一致，伴侣将Cu+直接递送到Cu+- atp酶的跨膜运输位点。
As in other P-type ATPases, metal binding to transmembrane metal-binding sites (TIMI-MBS) in Cu+-ATPases is required for enzyme phosphorylation and subsequent transport. However, Cu+ does not access Cu+-ATPases in a free (hydrated) form but is bound to a chaperone protein. Cu+ transfer from Cu+ chaperones to regulatory cytoplasmic metal-binding domains (MBDs) present in these ATPases has been described, but there is no evidence of a proposed subsequent Cu+ movement from the MBDs to the TM-MIBS. Alternatively, we postulate the parsimonious Cu+ transfer by the chaperone directly to TM-MBS. Testing both models, the delivery of Cu+ by Archaeoglobus fulgidus Cu+ chaperone CopZ to the corresponding Cu+-ATPase, CopA, was studied. As expected, CopZ interacted with and delivered the metal to CopA MBDs. Cu+-loaded MBDs, acting as metal donors, were unable to activate CopA or a truncated CopA lacking MBDs. Conversely, Cu+-loaded CopZ activated the CopA ATIPase and CopA constructs in which MBDs were rendered unable to bind Cu+. Furthermore, under nonturnover conditions, CopZ transferred Cu+ to the TM-MBS of a CopA lacking MBDs. These data are consistent with a model where MBDs serve a regulatory function without participating in metal transport and the chaperone delivers Cu+ directly to transmembrane transport sites of Cu+-ATPases.