Crystal structure of the N-terminal domain of linker LR and the assembly of cyanobacterial phycobilisome rods
Crystal structure of the N-terminal domain of linker LR and the assembly of cyanobacterial phycobilisome rods
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连接子LR的N端结构域的晶体结构和蓝藻藻胆体棒的组装
DOI：
10.1111/j.1365-2958.2011.07844.x
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发表时间：
2011-11-01
影响因子：
3.6
通讯作者：
Zhang，Yu-Zhong
中科院分区：
文献类型：
--
作者：
Gao，Xiang;Zhang，Nan;Zhang，Yu-Zhong
藻胆体是蓝藻和红藻中捕光的超分子复合体。连接子在藻胆体的组装和能量传递调节中起着关键作用。然而，由于缺乏连接体的结构和生化研究，特别是LR的N-末端结构域(Pami00427)，连接体的功能仍然不清楚。在这里，我们报告了来自Synechcystissp的连接子LR30的pam00427结构域的晶体结构。PCC6803，为1.9 ？PFAM00427呈现为以前未描述的对称点对称的六α-螺旋束。为了阐明C-藻蓝蛋白(C-PC)(αβ)6六聚体中pFAM00427的结合方式，我们利用AutoDock程序将pFAM00427计算固定在C-PC(αβ)6六聚体的内腔中。结合pFAM00427上保守的“C-PC结合补丁”，我们得到了pFAM00427-C-PC(αβ)6复合体的模型。通过分子动力学模拟对该模型进行了进一步的优化和评价，得到了较为合理的结果。在所得到的模型中，pami00427结构域稳定地定位在C-PC三聚体的中心孔中。此外，LRT(Pami01383)被对接到我们的pami00427-C-PC模型中，以产生一个完整的藻胆体杆，在该杆中，连接子与单个胆蛋白六聚体相连。
Phycobilisomes are light‐harvesting supramolecular complexes in cyanobacteria and red algae. Linkers play a pivotal role in the assembly and energy transfer modulation of phycobilisomes. However, how linkers function remains unclear due to the lack of structural and biochemical studies of linkers, especially the N‐terminal domain of LR(pfam00427). Here, we report the crystal structure of the pfam00427 domain of the linker LR30fromSynechocystissp. PCC 6803 at 1.9 Å. The pfam00427 presents as a previously uncharacterized point symmetric six α‐helix bundle. To elucidate the binding style of pfam00427 in the C‐phycocyanin (C‐PC) (αβ)6hexamer, we fixed pfam00427 computationally into the C‐PC (αβ)6inner cavity using the program AutoDock. Combined with a conserved ‘C‐PC binding patch’ on pfam00427 identified, we arrived at a model for the pfam00427–C‐PC (αβ)6complex. This model was further optimized and evaluated as a reasonable result by a molecular dynamics simulation. In the resulting model, the pfam00427 domain is stably positioned in the central hole of the C‐PC trimer. Moreover, the LRT(pfam01383) was docked into our pfam00427–C‐PC model to generate a complete phycobilisome rod in which the linkers join individual biliprotein hexamers.