A small family of LLS1-related non-heme oxygenases in plants with an origin amongst oxygenic photosynthesizers
A small family of LLS1-related non-heme oxygenases in plants with an origin amongst oxygenic photosynthesizers
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DOI：
10.1023/b:plan.0000028766.61559.4c
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发表时间：
2004-01-01
影响因子：
5.1
通讯作者：
Pauli, F
中科院分区：
文献类型：
--
作者：
Gray, J;Wardzala, E;Pauli, F
包括苔藓的陆生植物中致死性叶斑1（Lls 1）病变模拟基因的保守性与其最近报道的作为脱镁叶绿酸a加氧酶（Pao）的功能一致，所述加氧酶催化叶绿素降解中的关键步骤（Pruzinska et al.，2003年）。完整植物基因组的生物信息学调查显示，LLS 1（PAO）属于一个由Rieske和单核铁结合结构域定义的非血红素加氧酶小家族。该基因家族包括叶绿素a加氧酶（Cao）、胆碱单加氧酶（Cmo）、与通过叶绿体内膜的蛋白质运输相关的55 kDa蛋白质的基因（Tic 55）和从叶绿体分离的新的52 kDa蛋白质（Ptc 52）。基因结构分析表明，这些基因的分歧之前，单子叶/双子叶分化。在几种蓝细菌的基因组中发现了LLS 1（PAO）、CAO、TIC 55和PTC 52的同源物，但没有发现CMO。LLS 1（PAO）、PTC 52、TIC 55和一组相关的蓝藻同源物共享一个延长的羧基末端，其含有CAO中不存在的新的F/Y/W-x（2）-H-x（3）-C-x（2）-C基序。这些蛋白质似乎在向产氧光合作用过渡的过程中进化，在叶绿素代谢中发挥各种作用。相比之下，CMO同源物仅在植物中发现，并且与土壤细菌的芳香环羟化酶关系最密切，这表明这种酶可能是最近通过水平基因转移进化的。我们的系统发育分析95现存的非血红素双加氧酶提供了一个有用的框架LLS 1（PAO）相关的非血红素加氧酶的分类。
Conservation of Lethal-leaf spot 1 (Lls1) lesion mimic gene in land plants including moss is consistent with its recently reported function as pheophorbide a oxygenase (Pao) which catalyzes a key step in chlorophyll degradation (Pruzinska et al., 2003). A bioinformatics survey of complete plant genomes reveals that LLS1( PAO) belongs to a small 5-member family of non-heme oxygenases defined by the presence of Rieske and mononuclear iron-binding domains. This gene family includes chlorophyll a oxygenase (Cao), choline monooxygenase (Cmo), the gene for a 55 kDa protein associated with protein transport through the inner chloroplast membrane (Tic55) and a novel 52 kDa protein isolated from chloroplasts (Ptc52). Analysis of gene structure reveals that these genes diverged prior to monocot/dicot divergence. Homologues of LLS1( PAO), CAO, TIC55 and PTC52 but not CMO are found in the genomes of several cyanobacteria. LLS1( PAO), PTC52, TIC55 and a set of related cyanobacterial homologues share an extended carboxyl terminus containing a novel F/Y/W-x(2)-H-x(3)-C-x(2)-C motif not present in CAO. These proteins appear to have evolved during the transition to oxygenic photosynthesis to play various roles in chlorophyll metabolism. In contrast, CMO homologues are found only in plants and are most closely related to aromatic ring-hydroxylating enzymes from soil-dwelling bacteria, suggesting a more recent evolution of this enzyme, possibly by horizontal gene transfer. Our phylogenetic analysis of 95 extant non-heme dioxygenases provides a useful framework for the classification of LLS1( PAO)-related non-heme oxygenases.