>TIGR00978 asd_EA aspartate-semialdehyde dehydrogenase; InterPro: IPR005676 Bacteria, plants and fungi metabolise aspartic acid to produce four amino acids - lysine, threonine, methionine and isoleucine - in a series of reactions known as the aspartate pathway. Additionally, several important metabolic intermediates are produced by these reactions, such as diaminopimelic acid, an essential component of bacterial cell wall biosynthesis, and dipicolinic acid, which is involved in sporulation in Gram-positive bacteria. Members of the animal kingdom do not posses this pathway and must therefore acquire these essential amino acids through their diet. Research into improving the metabolic flux through this pathway has the potential to increase the yield of the essential amino acids in important crops, thus improving their nutritional value. Additionally, since the enzymes are not present in animals, inhibitors of them are promising targets for the development of novel antibiotics and herbicides. For more information see . Aspartate-semialdehyde dehydrogenase, the second enzyme in the aspartate pathway, converts aspartyl phosphate to aspartate-semialdehyde, the branch point intermediate between the lysine and threonine/methionine pathways. Based on sequence alignments, the aspartate-semialdehyde dehydrogenase family appears to have two distinct subgroups, one found in most bacteria (Gram-positve and Gram-negative), while the other is found primarily in organisms lacking peptidoglycan (archaea,fungi and some bacteria). Most studies have been performed on enzymes isolated from Gram-negative bacteria , , , . The N-terminal domain forms the active site and NADP-binding pocket, while C-terminal domain is primarily involved in hydrophobic intersubunit contacts. The catalytic mechanism involves the formation of a covalent thioester acyl-enzyme intermediate mediated through nucleophilic attack by an active site cysteine residue on the substrate aspartyl phosphate. Release of inorganic phosphate is followed by hydride transfer from NADPH to yield the product. The recently described archaeal structure suggests that the two subgroups of aspartate semi-aldehyde dehydrogenase share similar structures and have an identical catalytic mechanism, despite their relatively low sequence identity . Unlike the bacterial enzymes, the archaeal enzyme utilised both NAD and NADP as cofactor. This entry represents the subgroup of aspartate dehydrogenases found primarily in organisms lacking peptidoglycan. In addition to its role in aspartate metabolism, the enzyme from Sulfolobus solfataricus has been shown recently to exhibit RNase activity, suggesting that these enzymes may perform additional cellular functions .; GO: 0004073 aspartate-semialdehyde dehydrogenase activity, 0009086 methionine biosynthetic process, 0009088 threonine biosynthetic process.

Probab=94.44  E-value=0.052  Score=31.65  Aligned_cols=94  Identities=5%  Similarity=-0.136  Sum_probs=42.9

Q ss_pred             CCCCCCCCCCCCCCCCCCC-CCCCCC-CHHHHCCCCEEEE-EEEEC---CCC-CCEEEEEEEEEEECCCCCCCHH-----
Q ss_conf             3444322343322222344-444342-0133216711368-87520---343-3202789999863257754489-----
Q gi|254780294|r  162 QKNMPDTISSNHFFYSLDL-LHKHLP-EITQYSLIKTSPM-FLPSV---GRF-PQGIAIQISLDMERLSWKTNSE-----  229 (311)
Q Consensus       162 ~~~~~~~~~~~~~~~~~~~-~~~h~~-e~~~~~~~~~~~~-~~~~~---~~~-~~g~~~~v~v~~~~~~~~~~~~-----  229 (311)
T Consensus       180 mQAvSGAGY~GVp~~~I~dN~iP~I~GEE~KIe~E~~KilsGkl~~g~~~PA~~~~~at~~RVPV~~GHt~~v~v~~~~~  259 (358)
T TIGR00978       180 MQAVSGAGYPGVPSMDILDNVIPHIGGEEEKIERETLKILSGKLENGKIEPAEFEVSATTTRVPVLDGHTESVHVEFDKK  259 (358)
T ss_pred             ECCHHCCCCCCCCHHHHHCCCCCCCCCHHHHHHHHHHHHHCCCCCCCEEEEECCEEEEEEEECCCCCCCEEEEEEEECCC
T ss_conf             20001488888754555336165506335898762133334400388464204406899874441116469999986687


Q ss_pred             -HHHHHHHHHHCCCCCCEEECCCCCCC
Q ss_conf             -98866542200144305602787887
Q gi|254780294|r  230 -ELHSIFQEYYMGQNIVSVVPLEESRK  255 (311)
Q Consensus       230 -~~~~~~~~~~~~~~~v~v~~~~~~~~  255 (311)
T Consensus       260 ~d~~EI~~~~~~f~~~Pq~l~lP~~P~  286 (358)
T TIGR00978       260 FDIEEIREALKSFRGLPQKLGLPSAPE  286 (358)
T ss_pred             CCHHHHHHHHHHCCCCCCCCCCCCCCC
T ss_conf             798999999984067764257798869