title: Cryo-EM structure of fatty acid synthase (FAS) from Rhodosporidium toruloides provides insights into the evolutionary development of fungal FAS.
abstract: Fungal fatty acid synthases Type I (FAS I) are up to 2.7 MDa large molecular machines composed of large multifunctional polypeptides. Half of the amino acids in fungal FAS I are involved in structural elements that are responsible for scaffolding the elaborate barrel-shaped architecture and turning fungal FAS I into highly efficient de novo producers of fatty acids. Rhodosporidium toruloides is an oleaginous fungal species and renowned for its robust conversion of carbohydrates into lipids to over 70% of its dry cell weight. Here, we use cryo-EM to determine a 7.8-Å reconstruction of its FAS I that reveals unexpected features; its novel form of splitting the multifunctional polypeptide chain into the two subunits α and β, and its duplicated ACP domains. We show that the specific distribution into α and β occurs by splitting at one of many possible sites that can be accepted by fungal FAS I. While, therefore, the specific distribution in α and β chains in R. toruloides FAS I is not correlated to increased protein activities, we also show that the duplication of ACP is an evolutionary late event and argue that duplication is beneficial for the lipid overproduction phenotype.
authors.affiliation: Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Cluster of Excellence for Macromolecular Complexes, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Fischer
authors.affiliation: Department of Structural Biology, Max-Planck-Institute of Biophysics, 60438, Frankfurt, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rhinow
authors.affiliation: Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, 116023, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Structural Biology, Max-Planck-Institute of Biophysics, 60438, Frankfurt, Germany.
authors.forename: Deryck J
authors.initials: DJ
authors.lastname: Mills
authors.affiliation: Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, Dalian, 116023, China.|Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, Dalian, 116023, China.
authors.forename: Zongbao K
authors.initials: ZK
authors.lastname: Zhao
authors.affiliation: Department of Structural Biology, Max-Planck-Institute of Biophysics, 60438, Frankfurt, Germany.
authors.forename: Janet
authors.initials: J
authors.lastname: Vonck
authors.affiliation: Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, Cluster of Excellence for Macromolecular Complexes, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Grininger
mesh_terms: D020285:Cryoelectron Microscopy; D064429:Fatty Acid Synthases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014587:Ustilaginales / Q000201:enzymology*
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D064429:Fatty Acid Synthases
keywords: acyl carrier protein; biofuel; mega-enzyme; multifunctional proteins; protein assembly