The TL29 Protein is Lumen Located, Associated with PSII and Not an Ascorbate Peroxidase
The TL29 Protein is Lumen Located, Associated with PSII and Not an Ascorbate Peroxidase
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DOI：
10.1093/pcp/pcp134
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发表时间：
2009-11-01
影响因子：
4.9
通讯作者：
Schroder, Wolfgang P.
中科院分区：
文献类型：
--
作者：
Granlund, Irene;Storm, Patrik;Schroder, Wolfgang P.
TL29 蛋白是植物叶绿体类囊体腔中最丰富的蛋白质之一。基于其与抗坏血酸过氧化物酶的序列同源性，但没有任何生化证据支持，TL29被认为参与植物针对活性氧的防御系统，因此更名为APX4。我们的体内和体外分析未能显示任何与 TL29 相关的过氧化物酶活性；它既不结合血红素也不结合抗坏血酸。重组过表达的TL29不具有抗坏血酸依赖性过氧化物酶活性，并且旨在将TL29转化为抗坏血酸过氧化物酶的各种突变分析失败。此外，在类囊体腔中，没有这种活性与TL29相关，此外，TL29敲除突变体在光胁迫下生长时没有表现出任何过氧化物酶活性降低或自由基氧含量增加。相反，我们可以证明 TL29 是与 PSII 相关的位于管腔的成分。
The TL29 protein is one of the more abundant proteins in the thylakoid lumen of plant chloroplasts. Based on its sequence homology to ascorbate peroxidases, but without any supporting biochemical evidence, TL29 was suggested to be involved in the plant defense system against reactive oxygen species and consequently renamed to APX4. Our in vivo and in vitro analyses failed to show any peroxidase activity associated with TL29; it bound neither heme nor ascorbate. Recombinant overexpressed TL29 had no ascorbate-dependent peroxidase activity, and various mutational analyses aiming to convert TL29 into an ascorbate peroxidase failed. Furthermore, in the thylakoid lumen no such activity could be associated with TL29 and, additionally, TL29 knock-out mutants did not show any decreased peroxidase activity or increased content of radical oxygen species when grown under light stress. Instead we could show that TL29 is a lumen-located component associated with PSII.