title: 7.5-Å cryo-em structure of the mycobacterial fatty acid synthase.
abstract: The mycobacterial fatty acid synthase (FAS) complex is a giant 2.0-MDa α(6) homohexameric multifunctional enzyme that catalyzes synthesis of fatty acid precursors of mycolic acids, which are major components of the cell wall in Mycobacteria and play an important role in pathogenicity. Here, we present a three-dimensional reconstruction of the Mycobacterium smegmatis FAS complex at 7.5Å, highly homologous to the Mycobacterium tuberculosis multienzyme, by cryo-electron microscopy. Based on the obtained structural data, which allowed us to identify secondary-structure elements, and sequence homology with the fungal FAS, we generated an accurate architectural model of the complex. The FAS system from Mycobacteria resembles a minimized version of the fungal FAS with much larger openings in the reaction chambers. These architectural features of the mycobacterial FAS may be important for the interaction with mycolic acid processing and condensing enzymes that further modify the precursors produced by FAS and for autoactivation of the FAS complex.
authors.affiliation: Institute of Molecular Biology and Biophysics, ETH Zurich, Schafmattstrasse 20, 8093 Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Boehringer
authors.forename: Nenad
authors.initials: N
authors.lastname: Ban
authors.forename: Marc
authors.initials: M
authors.lastname: Leibundgut
mesh_terms: D001665:Binding Sites; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D064429:Fatty Acid Synthases / Q000737:chemistry* / Q000648:ultrastructure; D008958:Models, Molecular; D020102:Mycobacterium smegmatis / Q000201:enzymology*; D017434:Protein Structure, Tertiary
chemical_list: D064429:Fatty Acid Synthases