As of late 2007, 18
structures have been solved for this class of enzymes, with
PDB accession codes , , , , , , , , , , , , , , , , , and . In
yeast other
fungi and
bacteria participating in
assimilatory sulfate reduction, the sulfate adenylyltransferase is in the form a of a homohexamer. Its shape is that of a homotetramer in plants. In
Saccharomyces cerevisiae, sulfate adenylyltransferase is composed of four domains. Domain I features the N-terminus with beta-barrels similar to
pyruvate kinase. A right handed alpha/beta fold makes of the shape of Domain II, and it also contains the active site and substrate-binding pocket. Domain III is composed of a region linking the terminal domain to Domain I & II. Domain IV contains the C-terminus of the protein and forms a typical alpha/beta-fold. The active site is located in the center of the sulfate adenylyltransferase above the Domain II between the other domains I and II. The core of the groove in which the active site is located is mostly composed of
hydrophobic residues, but towards the outside of the groove are positive and
hydrophilic residues necessary for substrate binding. == Applications ==