A new class of hybrid secretion system is employed in Pseudomonas amyloid biogenesis

作者：Rouse Sarah L; Hawthorne William J; Berry Jamie Lee; Chorev Dror S; Ionescu Sandra A; Lambert Sebastian; Stylianou Fisentzos; Ewert Wiebke; Mackie Uma; Morgan R Marc L; Otzen Daniel; Herbst Florian Alexander; Nielsen Per H; Dueholm Morten; Bayley Hagan; Robinson Carol V; Hare Stephen; Matthews Stephen

来源：Nature Communications, 2017, 8(1): 263.

DOI：10.1038/s41467-017-00361-6

Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits for construction of a biofilm matrix. The secretion of bacterial functional amyloid requires a bespoke outer-membrane protein channel through which unfolded amyloid substrates are translocated. Here, we combine X-ray crystallography, native mass spectrometry, single-channel electrical recording, molecular simulations and circular dichroism measurements to provide high-resolution structural insight into the functional amyloid transporter from Pseudomonas, FapF. FapF forms a trimer of gated beta-barrel channels in which opening is regulated by a helical plug connected to an extended coil-coiled platform spanning the bacterial periplasm. Although FapF represents a unique type of secretion system, it shares mechanistic features with a diverse range of peptide translocation systems. Our findings highlight alternative strategies for handling and export of amyloid protein sequences.

• 出版日期2017-8-15