Aspartate aminotransferase, domain structure

Aspartate aminotransferase (AAT) is the first PLP-dependent enzyme for which the three-dimensional structure has been determined " " and is the prototype of fold-type I PLP-enzymes. Each subunit of the AAT homodimer has a large and a small domain. The coenzyme is bound to the large (N-terminal) domain and located in a pocket at the subunit interface, so that residues from each monomer contribute to the formation of both active sites. The proximal and distal carboxylate group of the dicarboxylic substrates bind to Arg386 and Arg292, respectively, the latter contributed by the opposite subunit. " Early crystallographic strucmres... 

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