Chaplins of Streptomyces coelicolor self-assemble into two distinct functional amyloids

详细信息    查看全文

• 作者：Marcel Bokhove ; Dennis Claessen ; Wouter de Jong ; Lubbert Dijkhuizen ; Egbert J. Boekema ; Gert T. Oostergetel
• 关键词：Streptomyces ; Amyloid ; Chaplin ; Cross-beta structure ; Cryo-electron tomography ; Electron diffraction
• 刊名：Journal of Structural Biology
• 出版年：November, 2013
• 年：2013
• 卷：184
• 期：2
• 页码：301-309
• 全文大小：6044 K

文摘

Chaplins are small, secreted proteins of streptomycetes that play instrumental roles in the formation of aerial hyphae and attachment of hyphae to surfaces. Here we show that the purified proteins self-assemble at a water/air interface into an asymmetric and amphipathic protein membrane that has an amyloid nature. Cryo-tomography reveals that the hydrophilic surface is relatively smooth, while the hydrophobic side is highly structured and characterized by the presence of small fibrils, which are similar to those observed on the surfaces of aerial hyphae. Interestingly, our work also provides evidence that chaplins in solution assemble into amyloid fibrils with a distinct morphology. These hydrophilic fibrils strongly resemble the structures known to be involved in attachment of Streptomyces hyphae to surfaces. These data for the first time show the assembly of bacterial proteins into two distinct amyloid structures that have different and relevant functions in vivo.