The Arabidopsis CRUMPLED LEAF protein, a homolog of the cyanobacterial bilin lyase, retains the bilin-binding pocket for a yet unknown function
The Arabidopsis CRUMPLED LEAF protein, a homolog of the cyanobacterial bilin lyase, retains the bilin-binding pocket for a yet unknown function
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拟南芥皱叶蛋白是蓝细菌胆素裂解酶的同源物，保留了胆素结合袋，但功能尚不清楚
DOI：
10.1111/tpj.14974
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发表时间：
2020-09-21
期刊：
影响因子：
7.2
通讯作者：
Kim，Chanhong
中科院分区：
文献类型：
--
作者：
Wang，Fangfang;Fang，Jun;Kim，Chanhong
光合细菌藻胆蛋白裂解酶，也称为 CpcT 裂解酶，通过发色团与天线蛋白的共价连接来催化藻胆体（一种光捕获天线复合物）的生物发生。拟南芥皱叶 (CRL) 蛋白是蓝藻 CpcT 裂解酶的同源物。 CRL 的缺失会导致多种病变，包括局部叶细胞死亡、应激相关核基因的组成型表达、细胞周期异常和质体分裂受损。尽管有明显的表型，CRL 的功能仍然难以捉摸。为了深入了解 CRL 的功能，我们检查了 CRL 是否仍保留与细菌发色团藻蓝蛋白 (PCB) 及其植物类似物植物色素蛋白 (PΦB) 结合的能力。尽管序列同一性较低，但 CRL 的 CpcT 结构域的揭示结构与 CpcT 裂解酶的结构相当。随后的体外生化测定发现，如 CpcT 裂解酶所示，PCB/PΦB 与 CRL 二聚体结合。然而，CRL 的一些突变形式，其胆素结合能力显着受损，但仍然恢复了 CRL 诱导的多重损伤。这些结果表明，虽然 CRL 保留了 bilin 结合袋，但它似乎与 crl 诱导的多发性病变在功能上没有关联。
The photosynthetic bacterial phycobiliprotein lyases, also called CpcT lyases, catalyze the biogenesis of phycobilisome, a light‐harvesting antenna complex, through the covalent attachment of chromophores to the antenna proteins. The Arabidopsis CRUMPLED LEAF (CRL) protein is a homolog of the cyanobacterial CpcT lyase. Loss of CRL leads to multiple lesions, including localized foliar cell death, constitutive expression of stress‐related nuclear genes, abnormal cell cycle, and impaired plastid division. Notwithstanding the apparent phenotypes, the function of CRL still remains elusive. To gain insight into the function of CRL, we examined whether CRL still retains the capacity to bind with the bacterial chromophore phycocyanobilin (PCB) and its plant analog phytochromobilin (PΦB). The revealed structure of the CpcT domain of CRL is comparable to that of the CpcT lyase, despite the low sequence identity. The subsequentin vitrobiochemical assays found, as shown for the CpcT lyase, that PCB/PΦB binds to the CRL dimer. However, some mutant forms of CRL, substantially compromised in their bilin‐binding ability, still restore thecrl‐induced multiple lesions. These results suggest that although CRL retains the bilin‐binding pocket, it seems not functionally associated with thecrl‐induced multiple lesions.