Mol Plant Microbe Interact. 2013 Nov;26(11):1281-93. doi: 10.1094/MPMI-05-13-0148-R.
Cerato-platanins (CP) are small, cysteine-rich fungal-secreted proteins involved in the various stages of the host-fungus interaction process, acting as phytotoxins, elicitors, and allergens. We identified 12 CP genes (MpCP1 to MpCP12) in the genome of Moniliophthora perniciosa, the causal agent of witches' broom disease in cacao, and showed that they present distinct expression profiles throughout fungal development and infection. We determined the X-ray crystal structures of MpCP1, MpCP2, MpCP3, and MpCP5, representative of different branches of a phylogenetic tree and expressed at different stages of the disease. Structure-based biochemistry, in combination with nuclear magnetic resonance and mass spectrometry, allowed us to define specialized capabilities regarding self-assembling and the direct binding to chitin and N-acetylglucosamine (NAG) tetramers, a fungal cell wall building block, and to map a previously unknown binding region in MpCP5. Moreover, fibers of MpCP2 were shown to act as expansin and facilitate basidiospore germination whereas soluble MpCP5 blocked NAG6-induced defense response. The correlation between these roles, the fungus life cycle, and its tug-of-war interaction with cacao plants is discussed.
角蛋白（CP）是小的、富含半胱氨酸的真菌分泌蛋白，参与宿主-真菌相互作用过程的各个阶段，作为植物毒素、激发子和过敏原发挥作用。我们在可可疫病病原菌可可毛色二孢（Moniliophthora perniciosa）的基因组中鉴定了 12 个 CP 基因（MpCP1 至 MpCP12），并表明它们在真菌发育和感染过程中呈现出不同的表达模式。我们测定了 MpCP1、MpCP2、MpCP3 和 MpCP5 的 X 射线晶体结构，它们代表了系统发育树的不同分支，并且在疾病的不同阶段表达。基于结构的生物化学，结合核磁共振和质谱，使我们能够确定其在自我组装以及直接与几丁质和 N-乙酰氨基葡萄糖（NAG）四聚体（真菌细胞壁的构建块）结合方面的特殊能力，并在 MpCP5 中绘制了一个以前未知的结合区域。此外，MpCP2 的纤维被证明可以作为扩展素并促进担子孢子萌发，而可溶性 MpCP5 则阻止 NAG6 诱导的防御反应。讨论了这些作用、真菌生命周期及其与可可植物的拉锯式相互作用之间的相关性。
