Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Michalik, D.; Schaks, A.; Wessjohann, L. A.;One-Step Synthesis of Natural Product-Inspired Biaryl Ether-Cyclopeptoid Macrocycles by Double Ugi Multiple-Component Reactions of Bifunctional Building BlocksEur. J. Org. Chem.2007149-157(2007)DOI: 10.1002/ejoc.200600354
Isonitrile‐functionalized biaryl ethers can serve as key building blocks for the highly efficient one‐step production of natural product inspired‐macrocycles, with six or even twelve new bonds and rings with up to 50 members being formed in total yields of up to 51 %. Aliphatic diamine and diacid tethers give access to two different classes of N ‐substituted biaryl ether cyclopeptides, suitable for library construction. As part of a conceptual work on MiBs (m ultiple m ulticomponent m acrocyclizations/m acrocycles i ncluding b ifunctional b uilding b locks), the influence of length and type of flexible tethers on the propensity for cyclization is studied.
Publikation
Guranowski, A.; Miersch, O.; Staswick, P. E.; Suza, W.; Wasternack, C.;Substrate specificity and products of side-reactions catalyzed by jasmonate:amino acid synthetase (JAR1)FEBS Lett.581815-820(2007)DOI: 10.1016/j.febslet.2007.01.049
Jasmonate:amino acid synthetase (JAR1) is involved in the function of jasmonic acid (JA) as a plant hormone. It catalyzes the synthesis of several JA‐amido conjugates, the most important of which appears to be JA‐Ile. Structurally, JAR1 is a member of the firefly luciferase superfamily that comprises enzymes that adenylate various organic acids. This study analyzed the substrate specificity of recombinant JAR1 and determined whether it catalyzes the synthesis of mono‐ and dinucleoside polyphosphates, which are side‐reaction products of many enzymes forming acyl ∼ adenylates. Among different oxylipins tested as mixed stereoisomers for substrate activity with JAR1, the highest rate of conversion to Ile‐conjugates was observed for (±)‐JA and 9,10‐dihydro‐JA, while the rate of conjugation with 12‐hydroxy‐JA and OPC‐4 (3‐oxo‐2‐(2Z ‐pentenyl)cyclopentane‐1‐butyric acid) was only about 1–2% that for (±)‐JA. Of the two stereoisomers of JA, (−)‐JA and (+)‐JA, rate of synthesis of the former was about 100‐fold faster than for (+)‐JA. Finally, we have demonstrated that (1) in the presence of ATP, Mg2+, (−)‐JA and tripolyphosphate the ligase produces adenosine 5′‐tetraphosphate (p4A); (2) addition of isoleucine to that mixture halts the p4A synthesis; (3) the enzyme produces neither diadenosine triphosphate (Ap3A) nor diadenosine tetraphosphate (Ap4A) and (4) Ap4A cannot substitute ATP as a source of adenylate in the complete reaction that yields JA‐Ile.