The initial step in the archaeal aspartate biosynthetic pathway catalyzed by a monofunctional aspartokinase
The enzyme aspartokinase catalyzes the commitment step to amino acid biosynthesis in the aspartate pathway. The first structure of a microbial aspartokinase, isolated from
Methanococcus jannaschii, has been determined in the presence of the amino acid substrate, Laspartic acid, and the nucleotide product, MgADP. The enzyme assembles into a dimer of dimers both in the crystal and in solution. The active site groups responsible for substrate binding have been identified, and roles have been proposed for putative catalytic groups.
C.R. Faehnle, X. Liu, A. Pavlovsky and R.E. Viola
![[M. jannaschii]](https://www.iucr.org/__data/assets/image/0008/4958/en5196.gif)
The active site of M. jannaschii aspartokinase in a deep cleft formed between the C-terminal ACT regulatory domains (dark blue) and the Nterminal catalytic domain (light blue) within each subunit of the tetrameric enzyme.
