>gnl|CDD|153193 cd04921, ACT_AKi-HSDH-ThrA-like_1, ACT domains of the bifunctional enzyme aspartokinase (AK) - homoserine dehydrogenase (HSDH). This CD includes the first of two ACT domains of the bifunctional enzyme aspartokinase (AK) - homoserine dehydrogenase (HSDH). The ACT domains are positioned between the N-terminal catalytic domain of AK and the C-terminal HSDH domain found in bacteria (Escherichia coli (EC) ThrA) and higher plants (Zea mays AK-HSDH). AK and HSDH are the first and third enzymes in the biosynthetic pathway of the aspartate family of amino acids. AK catalyzes the phosphorylation of Asp to P-aspartyl phosphate. HSDH catalyzes the NADPH-dependent conversion of Asp 3-semialdehyde to homoserine. HSDH is the first committed reaction in the branch of the pathway that leads to Thr and Met. In E. coli, ThrA is subject to allosteric regulation by the end product L-threonine and the native enzyme is reported to be tetrameric. As with bacteria, plant AK and HSDH are feedback inhibited by pathway end products. Maize AK-HSDH is a Thr-sensitive 180-kD enzyme. Arabidopsis AK-HSDH is an alanine-activated, threonine-sensitive enzyme whose ACT domains were shown to be involved in allosteric activation. Also included in this CD is the first of two ACT domains of a tetrameric, monofunctional, threonine-sensitive, AK found in Methanococcus jannaschii and other related archaeal species. Members of this CD belong to the superfamily of ACT regulatory domains. Length = 80

 Score = 39.5 bits (93), Expect = 0.002
 Identities = 22/69 (31%), Positives = 38/69 (55%), Gaps = 4/69 (5%)

Query: 345 LVKISAIGIGMQSYAGVASAFFLCLAEKGINIKAIT--TSEIKISVLIDSAYTELAVRSL 402
           L+ I   G GM    G+A+  F  LA  GIN+  I+  +SE  IS ++D +  + A+ +L
Sbjct: 3   LINIE--GTGMVGVPGIAARIFSALARAGINVILISQASSEHSISFVVDESDADKALEAL 60

Query: 403 HSCYGLDVQ 411
              + L+++
Sbjct: 61  EEEFALEIK 69