Structural highlights
Function[HOSA_SULAC] Catalyzes the aldol-type condensation of 2-oxoglutarate with acetyl-CoA to yield homocitrate. Carries out the first step of the alpha-aminoadipate (AAA) lysine biosynthesis pathway. Does not display 2-isopropylmalate synthase and citramalate synthase activities since it cannot use 2-oxoisovalerate or pyruvate as substrate.[1] Publication Abstract from PubMedHomocitrate synthase (HCS) catalyzes the aldol condensation of alpha-ketoglutarate and acetyl coenzyme A to form homocitrate, which is the first committed step of lysine biosynthesis through the alpha-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 alpha-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. 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 FEBS J. 2020 Sep 8. doi: 10.1111/febs.15527. PMID:32897601[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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This page was last modified 11:22, 23 September 2020.