Structural insights into the cold adaptation of the photosynthetic pigment-protein C-phycocyanin from an Arctic cyanobacterium
Structural insights into the cold adaptation of the photosynthetic pigment-protein C-phycocyanin from an Arctic cyanobacterium
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北极蓝藻光合色素蛋白 C-藻蓝蛋白冷适应的结构见解
DOI：
10.1016/j.bbabio.2017.02.004
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发表时间：
2017
影响因子：
4.3
通讯作者：
Xie Bin-Bin
中科院分区：
文献类型：
--
作者：
Su Hai-Nan;Wang Qian-Min;Li Chun-Yang;Li Kang;Luo Wei;Chen Bo;Zhang Xi-Ying;Qin Qi-Long;Zhou Bai-Cheng;Chen Xiu-Lan;Zhang Yu-Zhong;Xie Bin-Bin
The cold adaptation mechanism of phycobiliproteins, the major photosynthetic pigment-proteins in cyanobacteria and red algae, has rarely been studied. Here we reported the biochemical, structural, and molecular dynamics simulation study of the C-phycocyanin from Arctic cyanobacterial strainPseudanabaenasp. LW0831. We characterized the phycobilisome components of LW0831 and obtained their gene sequences. Compared to the mesophilic counterpart fromArthrospira platensis(Ar-C-PC), LW0831 C-phycocyanin (Ps-C-PC) has a decreased thermostability (∆Tmof − 16 °C), one of the typical features of cold-adapted enzymes. To uncover its structural basis, we resolved the crystal structure of Ps-C-PC 1 at 2.04 Å. Consistent with the decrease in thermostability, comparative structural analyses revealed decreased intra-trimer and inter-trimer interactions in Ps-C-PC 1, compared to Ar-C-PC. However, comparative molecular dynamics simulations indicated that Ps-C-PC 1 shows similar flexibilities to Ar-C-PC for both the (αβ)3trimer and (αβ)6hexamer. Therefore, the optimization mode is clearly different from cold-adapted enzymes, which usually have increased flexibilities. Detailed analyses demonstrated different optimization modes for the α and β subunits and it was revealed that hydrophobic interactions are key to this difference, though salt bridges, hydrogen bonds, and surface hydrophobicity are also involved. This study is the first report of the structure of cold-adapted phycobiliproteins and provides insights into the cold-adaptation strategies of non-enzyme proteins.
