>gnl|CDD|58609 cd04243, AAK_AK-HSDH-like, AAK_AK-HSDH-like: Amino Acid Kinase Superfamily (AAK), AK-HSDH-like; this family includes the N-terminal catalytic domain of aspartokinase (AK) of the bifunctional enzyme AK- homoserine dehydrogenase (HSDH). These aspartokinases are found in such bacteria as E. coli (AKI-HSDHI, ThrA and AKII-HSDHII, MetL) and in higher plants (Z. 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. ThrA and MetL are involved in threonine and methionine biosynthesis, respectively. 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, located C-terminal to the AK catalytic domain, were shown to be involved in allosteric activation. Also included in this CD is the catalytic domain of the aspartokinase (AK) of the lysine-sensitive aspartokinase isoenzyme AKIII, a monofunctional class enzyme (LysC) found in some bacteria such as E. coli. In E. coli, LysC is reported to be a homodimer of 50 kD subunits. Also included in this CD is the catalytic domain of aspartokinase (AK) of the bifunctional enzyme AK - DAP decarboxylase (DapDC) found in some bacteria. DapDC, which is the lysA gene product, catalyzes the decarboxylation of DAP to lysine.. Length = 293

 Score =  162 bits (412), Expect = 1e-40
 Identities = 90/297 (30%), Positives = 139/297 (46%), Gaps = 59/297 (19%)

Query: 4   IVMKFGGTSVANIDCIRSAALHVKREVDRGQEV-------------AMVVSAMSGET--- 47
            V+KFGGTSVA+ + IR  A  +K        V             A+   A SG+    
Sbjct: 2   KVLKFGGTSVASAERIRRVADIIKSRASSPVLVVVSALGGVTNRLVALAELAASGDDAQA 61

Query: 48  ----------------------------------DRLAELCRQVTSIDNA--RERDVVIS 71
                                             +RL +L   +  +     + R  V+S
Sbjct: 62  IVLQEIRERHLDLIKELLSGESAAELLAALDSLLERLKDLLEGIRLLGELSDKTRAEVLS 121

Query: 72  TGEQVSSGLMVLALQSLGIQAISLQGWQIPIMTDSLHGMARICRVDEKKIVTHL--KKKQ 129
            GE +SS LM   LQ  G+ A  L   ++ ++TD     A +     K+ +  L  +  +
Sbjct: 122 FGELLSSRLMSAYLQEQGLPAAWLDAREL-LLTDDGFLNAVVDLKLSKERLAQLLAEHGK 180

Query: 130 VVVITGFQGLSHDNSVTTLGRGGSDTSAVAIAAAIKADRCDIYTDVCGIYTTDPRIEPKA 189
           VVV  GF   + D   TTLGRGGSD SA  +AA + A+  +I+TDV G+YT DPR  P A
Sbjct: 181 VVVTQGFIASNEDGETTTLGRGGSDYSAALLAALLDAEEVEIWTDVDGVYTADPRKVPDA 240

Query: 190 HLMKKISFEEMLEMSSLGAKVMQVRSVELAMLYKMCLFVRSSFEDHGQQEQLGTLIC 246
            L+K++S++E +E++  GAKV+  R+++ A+   + +F++++F      E  GTLI 
Sbjct: 241 RLLKELSYDEAMELAYFGAKVLHPRTIQPAIRKNIPIFIKNTFN----PEAPGTLIS 293