|A First Look at Yeast Fatty Acid Synthase| Fatty acids are the
major constituents of eukaryotic and bacterial cellular
membranes. They are used for functionally important post-
translational protein modifications, and chains of fatty acids
are the main storage compartments of an organism's chemical
energy. Fatty acid synthesis is carried out by fatty acid
sythase (FAS), which catalyzes cycles of multistep chemical
reactions that are essentially the same in all organisms. FAS
uses one acetyl-coenzyme A (CoA) and seven malonyl-CoA molecules
to synthesize the 16-carbon palmitic acid, the most abundant
fatty acid in eukaryotes. Now, for the first time, a group of
researchers has determined the atomic structure of yeast
Saccharomyces cerevisiae FAS derived from two crystals of the
enzyme, using data collected at ALS Beamlines 8.2.1 and 8.2.2,
as well as other synchrotron facilities. Determining the yeast
FAS structure was challenging because of its architectural
complexity. The yeast FAS consists of 48 functional