 | Acta Crystallographica Section D Acta Crystallographica Section D BIOLOGICAL CRYSTALLOGRAPHY |
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![[Figure 1]](ba5132fig1mag.jpg)
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Figure 1
Structural studies of fungal fatty acid synthase (FAS). The figure summarizes the flow of phase information between the different X-ray crystallographic and electron-microscopic (EM) systems for structural determination of fungal FAS at progressively higher resolution. (a) Low-resolution model of the multi-enzyme based on a three-dimensional reconstruction from EM images of negatively stained particles (Hackenjos & Schramm, 1987  ). (b) Three-dimensional single-particle reconstruction at 21 Å resolution from frozen-hydrated particles (Kolodziej et al., 1997). This EM map was used as a search model to derive molecular-replacement solutions for several crystal forms of fungal FAS (Jenni et al., 2006; Xiong, 2008). (c) 8 Å resolution electron-density map of T. lanuginosus FAS after crystal derivatization with Ta6Br12 heavy-atom clusters and SAD phasing in space group P212121 (Jenni et al., 2006). (d) Electron-density map in space group P21 of T. lanuginosus FAS phased at 5 Å resolution by cross-crystal and noncrystallographic symmetry (NCS) density averaging starting with phases from (c). At this resolution, molecular features were recognized and the map was interpreted by rigid-body fitting of structures from homologous individual enzymes (Jenni et al., 2006). (e) Cα model obtained from the fitted functional domains. (f) Refined atomic structure of FAS from T. lanuginosus (Jenni et al., 2007). This model was employed to phase the yeast FAS crystal structure by molecular replacement (g) (Leibundgut et al., 2007) and to initially determine the projection angles of class averages for the 15 Å resolution single-particle reconstruction of the enzyme (h) (Jenni et al., 2007). (i) Phases calculated from a molecular-replacement solution obtained from the Cα model were used to solve the structure of yeast FAS at 4 Å resolution (Lomakin et al., 2007). |
![[Figure 1]](ba5132fig1.jpg)
| BIOLOGICAL CRYSTALLOGRAPHY |
ISSN: 1399-0047
