Involvement of subdomain II in the recognition of acetyl-CoA revealed by the crystal structure of homocitrate synthase from Sulfolobus acidocaldarius.Suzuki, T., Tomita, T., Hirayama, K., Suzuki, M., Kuzuyama, T., Nishiyama, M.
(2021) FEBS J 288: 1975-1988
- PubMed: 32897601
- DOI: https://doi.org/10.1111/febs.15527
- Primary Citation of Related Structures:
- PubMed Abstract:
Homocitrate synthase (HCS) catalyzes the aldol condensation of α-ketoglutarate and acetyl coenzyme A to form homocitrate, which is the first committed step of lysine biosynthesis through the α-aminoadipate pathway in yeast, fungi, and some prokaryotes. We determined the crystal structure of a truncated form of HCS from a hyperthermophilic acidophilic archaeon, Sulfolobus acidocaldarius, which lacks the RAM (Regulation of amino acid metabolism) domain at the C terminus serving as the regulatory domain for the feedback inhibition by lysine, in complex with α-ketoglutarate, Mg 2+ , and CoA. This structure coupled with mutational analysis revealed that a subdomain, subdomain II, connecting the N-terminal catalytic domain and C-terminal RAM domain is involved in the recognition of acetyl-CoA. This is the first structural evidence of the function of subdomain II in the related enzyme family, which will lead to a better understanding of the catalytic mechanism of HCS. DATABASES: Structural data are available in the RCSB PDB database under the accession number 6KTQ.
Biotechnology Research Center, The University of Tokyo, Japan.