Evolution of a plant-specific copper chaperone family for chloroplast copper homeostasis
Evolution of a plant-specific copper chaperone family for chloroplast copper homeostasis
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DOI：
10.1073/pnas.1421545111
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发表时间：
2014-12-16
影响因子：
11.1
通讯作者：
Merchant, Sabeeha S.
中科院分区：
文献类型：
--
作者：
Blaby-Haas, Crysten E.;Padilla-Benavides, Teresita;Merchant, Sabeeha S.
金属伴侣将铜（Cu+）从质膜的进入点运输到其目的地。在植物中，一个目的地是叶绿体，其中容纳质体蓝蛋白，一种参与光合作用的铜依赖性电子转移蛋白。我们提出了一个以前未确定的铜+分子伴侣，进化早期的植物谱系的选择性剪接事件的前体mRNA编码的叶绿体P型ATP酶在拟南芥1（PAA 1）。在几种陆生植物中，最近的重复事件产生了一个单独的伴侣编码基因，与选择性剪接的丧失相一致。植物特异性Cu+分子伴侣递送对PAA 1具有特异性的Cu+，PAA 1相对于原型细菌ATP酶在包膜中翻转，与Cu+输入到基质中的作用相容，并且与这些酶的典型催化机制一致。伴侣蛋白的普遍存在表明这种Cu+递送机制的保守性，并提供了一个独特的快照到Cu+分布途径的演变。我们还提供了证据PAA 2，Cu+-ATP酶在类囊体，和Cu+-铜/锌超氧化物歧化酶（CCS）分子伴侣之间的相互作用，揭示了一个Cu+网络，已经发展到微调Cu+分布。
Metallochaperones traffic copper (Cu+) from its point of entry at the plasma membrane to its destination. In plants, one destination is the chloroplast, which houses plastocyanin, a Cu-dependent electron transfer protein involved in photosynthesis. We present a previously unidentified Cu+ chaperone that evolved early in the plant lineage by an alternative-splicing event of the pre-mRNA encoding the chloroplast P-type ATPase in Arabidopsis 1 (PAA1). In several land plants, recent duplication events created a separate chaperone-encoding gene coincident with loss of alternative splicing. The plant-specific Cu+ chaperone delivers Cu+ with specificity for PAA1, which is flipped in the envelope relative to prototypical bacterial ATPases, compatible with a role in Cu+ import into the stroma and consistent with the canonical catalytic mechanism of these enzymes. The ubiquity of the chaperone suggests conservation of this Cu+-delivery mechanism and provides a unique snapshot into the evolution of a Cu+ distribution pathway. We also provide evidence for an interaction between PAA2, the Cu+-ATPase in thylakoids, and the Cu+-chaperone for Cu/Zn superoxide dismutase (CCS), uncovering a Cu+ network that has evolved to fine-tune Cu+ distribution.