Taxonomic distribution of proteins containing Semialdhyde_dh domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing Semialdhyde_dh domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Structure of aspartate-beta-semialdehyde dehydrogenase from Escherichiacoli, a key enzyme in the aspartate family of amino acid biosynthesis.

Hadfield A, Kryger G, Ouyang J, Petsko GA, Ringe D, Viola R
J Mol Biol. 1999; 289: 991-1002

Aspartate beta-semialdehyde dehydrogenase (ASADH) lies at the first branchpoint in an essential aspartic biosynthetic pathway found in bacteria,fungi and the higher plants. Mutations in the asd gene encoding for ASADHthat produce an inactive enzyme are lethal, which suggests that ASADH maybe an effective target for antibacterial, herbicidal and fungicidalagents.We have solved the crystal structure of the Escherichia coli enzymeto 2.5 A resolution using single isomorphous replacement and 3-foldnon-crystallographic symmetry. Each monomer has an N-terminalnucleotide-binding domain and a dimerisation domain. The presence of anessential cysteine locates the active site in a cleft between the twodomains. The functional dimer has the appearance of a butterfly, with theNADP-binding domains forming the wings and the dimerisation domain formingthe body.A histidine residue is identified as a likely acid/base catalystin the enzymic reaction. Other amino acids implicated in the enzymicactivity by mutagenesis are found in the active site region and define thesubstrate binding pocket.