Crystal structure of phyllogen, a phyllody-inducing effector protein of phytoplasma
Crystal structure of phyllogen, a phyllody-inducing effector protein of phytoplasma
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DOI：
10.1016/j.bbrc.2019.04.060
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发表时间：
2019-06-11
影响因子：
3.1
通讯作者：
Namba, Shigetou
中科院分区：
文献类型：
--
作者：
Iwabuchi, Nozomu;Maejima, Kensaku;Namba, Shigetou
植原体是一种植物病原细菌，常引起独特的叶状症状，表现为花器官转化为叶状结构。最近，一个新的细菌效应基因家族，称为叶状诱导基因，被发现通过降解花MADS结构域转录因子(MTF)来诱导叶状结构。然而，叶系的结构特征尚不清楚。在这项研究中，我们以2.4埃的分辨率阐明了‘星状假丝酵母’洋葱黄色品系的叶型PHYL1(Oy)的晶体结构。PHYL1的结构由两个α-螺旋组成，由一个随机环以盘绕的方式连接。在两个α-螺旋中，疏水残基的分布在叶系之间是保守的。氨基酸插入到任何一个α-螺旋上的突变导致叶系诱导活性的丧失和叶状体降解花MTF的能力的丧失。相反，在环区的相同插入不影响任何一种活性，表明两个保守的α-螺旋对叶系基因的功能都很重要。这是首次报道植原体效应蛋白的晶体结构。(C)2019 Elsevier Inc.保留所有权利。
Phytoplasmas are plant pathogenic bacteria that often induce unique phyllody symptoms in which the floral organs are transformed into leaf-like structures. Recently, a novel family of bacterial effector genes, called phyllody-inducing genes (phyllogens), was identified as being involved in the induction of phyllody by degrading floral MADS-domain transcription factors (MTFs). However, the structural characteristics of phyllogens are unknown. In this study, we elucidated the crystal structure of PHYL1(OY), a phyllogen of 'Candidatus Phytoplasma asteris' onion yellows strain, at a resolution of 2.4 angstrom. The structure of PHYL1 consisted of two alpha-helices connected by a random loop in a coiled-coil manner. In both alpha-helices, the distributions of hydrophobic residues were conserved among phyllogens. Amino acid insertion mutations into either alpha-helix resulted in the loss of phyllody-inducing activity and the ability of the phyllogen to degrade floral MTF. In contrast, the same insertion in the loop region did not affect either activity, indicating that both conserved alpha-helices are important for the function of phyllogens. This is the first report on the crystal structure of an effector protein of phytoplasmas. (C) 2019 Elsevier Inc. All rights reserved.