Imperfect pseudo-merohedral twinning in crystals of fungal fatty acid synthase

Open access
Date
2009-02Type
- Journal Article
Abstract
The recent high-resolution structures of fungal fatty acid synthase (FAS) have provided new insights into the principles of fatty acid biosynthesis by large multifunctional enzymes. The crystallographic phase problem for the 2.6 MDa fungal FAS was initially solved to 5 Å resolution using two crystal forms from Thermomyces lanuginosus. Monoclinic crystals in space group P21 were obtained from orthorhombic crystals in space group P212121 by dehydration. Here, it is shown how this space-group transition induced imperfect pseudo-merohedral twinning in the monoclinic crystal, giving rise to a Moiré pattern-like interference of the two twin-related reciprocal lattices. The strategy for processing the twinned diffraction images and obtaining a quantitative analysis is presented. The twinning is also related to the packing of the molecules in the two crystal forms, which was derived from self-rotation function analysis and molecular-replacement solutions using a low-resolution electron microscopy map as a search model. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000019862Publication status
publishedExternal links
Journal / series
Acta Crystallographica Section D: Biological CrystallographyVolume
Pages / Article No.
Publisher
Wiley-BlackwellSubject
imperfect pseudo-merohedral twinning; fungal fatty acid synthaseMore
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