Biochemical characterization of archaeal homocitrate synthase from Sulfolobus acidocaldarius

• Published in: FEBS letters Vol. 594; no. 1; pp. 126 - 134
• Main Authors: Suzuki, Tomohiro, Akiyama, Nagisa, Yoshida, Ayako, Tomita, Takeo, Lassak, Kerstin, Haurat, Maria Florencia, Okada, Takuya, Takahashi, Kento, Albers, Sonja‐Verena, Kuzuyama, Tomohisa, Nishiyama, Makoto
• Format: Journal Article
• Language: English
• Published: England 01-01-2020
• Subjects: Archaea; homocitrate synthase; lysine biosynthesis; RAM domain; RAM domain; Archaea; lysine biosynthesis; homocitrate synthase
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1002/1873-3468.13550

The hyperthermophilic archaeon, Sulfolobus, synthesizes lysine via the α‐aminoadipate pathway; however, the gene encoding homocitrate synthase, the enzyme responsible for the first and committed step of the pathway, has not yet been identified. In the present study, we identified saci_1304 as the gene encoding a novel type of homocitrate synthase fused with a Regulation of Amino acid Metabolism (RAM) domain at the C terminus in Sulfolobus acidocaldarius. Enzymatic characterization revealed that Sulfolobus homocitrate synthase was inhibited by lysine; however, the mutant enzyme lacking the RAM domain was insensitive to inhibition by lysine. The present results indicated that the RAM domain is responsible for enzyme inhibition.