Schlumbohm W, Keller U
Institut für Biochemie und Molekulare Biologie, Technische Universität Berlin, Federal Republic of Germany.
J Biol Chem. 1990 Feb 5;265(4):2156-61.
A 3-hydroxypicolinic acid activating enzyme from etamycin producing Streptomyces griseoviridus has been purified to apparent homogeneity. Etamycin is a member of mikamycin B antibiotics, chromopeptide lactones, which contain 3-hydroxypicolinic acid (3-HPA) as the chromophoric group. The enzyme catalyzes both the 3-HPA-dependent ATP-pyrophosphate exchange and the formation of 3-HPA adenylate from 3-HPA and ATP. SDS-polyacrylamide gel electrophoresis indicates that the enzyme is a single polypeptide chain with a Mr between 56,000 and 58,000. The molecular mass of the native enzyme was in the same range. In addition to 3-HPA, the enzyme catalyzes the formation of adenylates from picolinic acid, nicotinic acid, and 2-pyrazinecarboxylic acid. Nicotinic acid and picolinic acid when added externally to etamycin producing S. griseoviridus cultures gave rise to the formation of etamycin analogues each containing nicotinic acid or picolinic acid instead of the genuine 3-HPA. The data strongly suggest that the enzyme is involved in the biosynthesis of the chromopeptide lactone etamycin and possibly in that of other mikamycin B antibiotics.
从产埃他霉素的灰绿链霉菌中纯化出一种3-羟基吡啶甲酸激活酶，达到了表观均一性。埃他霉素是米卡霉素B类抗生素（即色肽内酯）的一种，其发色基团为3-羟基吡啶甲酸（3-HPA）。该酶既能催化依赖3-HPA的ATP-焦磷酸交换反应，也能催化由3-HPA和ATP形成3-HPA腺苷酸的反应。SDS-聚丙烯酰胺凝胶电泳表明，该酶是一条单多肽链，相对分子质量在56,000至58,000之间。天然酶的分子量也在相同范围内。除了3-HPA外，该酶还能催化由吡啶甲酸、烟酸和2-吡嗪羧酸形成腺苷酸。当向产埃他霉素的灰绿链霉菌培养物中额外添加烟酸和吡啶甲酸时，会产生埃他霉素类似物，每种类似物都含有烟酸或吡啶甲酸，而非真正的3-HPA。这些数据有力地表明，该酶参与了色肽内酯埃他霉素的生物合成，可能还参与了其他米卡霉素B类抗生素的生物合成。
