title: The propensity of the bacterial rodlin protein RdlB to form amyloid fibrils determines its function in Streptomyces coelicolor.
abstract: Streptomyces bacteria form reproductive aerial hyphae that are covered with a pattern of pairwise aligned fibrils called rodlets. The presence of the rodlet layer requires two homologous rodlin proteins, RdlA and RdlB, and the functional amyloid chaplin proteins, ChpA-H. In contrast to the redundancy shared among the eight chaplins, both RdlA and RdlB are indispensable for the establishment of this rodlet structure. By using a comprehensive biophysical approach combined with in vivo characterization we found that RdlB, but not RdlA, readily assembles into amyloid fibrils. The marked difference in amyloid propensity between these highly similar proteins could be largely attributed to a difference in amino acid sequence at just three sites. Further, an engineered RdlA protein in which these three key amino acids were replaced with the corresponding residues from RdlB could compensate for loss of RdlB and restore formation of the surface-exposed amyloid layer in bacteria. Our data reveal that RdlB is a new functional amyloid and provide a biophysical basis for the functional differences between the two rodlin proteins. This study enhances our understanding of how rodlin proteins contribute to formation of an outer fibrillar layer during spore morphogenesis in streptomycetes.
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Yang
authors.affiliation: Molecular Biotechnology, Institute of Biology, Leiden University, 2333 BE Leiden, the Netherlands.
authors.forename: Joost
authors.initials: J
authors.lastname: Willemse
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Sawyer
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.|University of the Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Lou
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Gong
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.|University of the Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biomolecular Engineering and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, 3010 VIC, Australia.
authors.forename: Sally L
authors.initials: SL
authors.lastname: Gras
authors.affiliation: Molecular Biotechnology, Institute of Biology, Leiden University, 2333 BE Leiden, the Netherlands.
authors.forename: Dennis
authors.initials: D
authors.lastname: Claessen
authors.affiliation: National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.|University of the Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Sarah
authors.initials: S
authors.lastname: Perrett
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009154:Mutation; D000072757:Protein Conformation, beta-Strand; D013171:Spores, Bacterial / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D048372:Streptomyces coelicolor / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D000682:Amyloid; D001426:Bacterial Proteins