HMM Summary Page: TIGR00656

Functionaspartate kinase, monofunctional class
Trusted Cutoff402.25
Domain Trusted Cutoff402.25
Noise Cutoff355.20
Domain Noise Cutoff355.20
Isology Typeequivalog
EC Number2.7.2.4
HMM Length407
Mainrole CategoryAmino acid biosynthesis
Subrole CategoryAspartate family
Gene Ontology TermGO:0004072: aspartate kinase activity molecular_function
GO:0009089: lysine biosynthetic process via diaminopimelate biological_process
AuthorHaft DH
Entry DateDec 1 1999 10:45AM
Last ModifiedFeb 25 2011 12:36PM
CommentThis model describes a subclass of aspartate kinases. These are mostly Lys-sensitive and not fused to homoserine dehydrogenase, unlike some Thr-sensitive and Met-sensitive forms. Homoserine dehydrogenase is part of Thr and Met but not Lys biosynthetic pathways. Aspartate kinase catalyzes a first step in the biosynthesis from Asp of Lys (and its precursor diaminopimelate), Met, and Thr. In E. coli, a distinct isozyme is inhibited by each of the three amino acid products. The Met-sensitive (I) and Thr-sensitive (II) forms are bifunctional enzymes fused to homoserine dehydrogenases and form homotetramers, while the Lys-sensitive form (III) is a monofunctional homodimer. The Lys-sensitive enzyme of Bacillus subtilis resembles the E. coli form but is an alpha 2/beta 2 heterotetramer, where the beta subunit is translated from an in-phase alternative initiator at Met-246. The protein slr0657 from Synechocystis PCC6803 is extended by a duplication of the C-terminal region corresponding to the beta chain. Incorporation of a second copy of the C-terminal domain may be quite common in this subgroup of aspartokinases.
ReferencesA2 hmmalign GA hmmsearch AL clustalw_manual DR EXPERIMENTAL; EGAD|9629|EC4024; monofunctional, Lys-sensitive homodimer DR EXPERIMENTAL; EGAD|15096|BS2841; monofunctional, Lys-sensitive heterotetramer DR EXPERIMENTAL; EGAD|24158|BS1676; monofunctional, diaminopimelate-sensitive heterotetramer DR OUTGROUP; EGAD|9487|EC0002; bifunctional, Thr-sensitive homotetramer DR OUTGROUP; EGAD|21696|EC3940; bifunctional, Met-sensistive homotetramer DR OUTGROUP; EGAD|52194|YER052C; mostly Thr-sensitive DR OUTGROUP; EGAD|75283|81007; bifunctional, chloroplast
Genome PropertyGenProp0160: aspartate semialdehyde biosynthesis from aspartate (HMM)