Topological Study of Mechanistic Diversity in Conjugated Fatty Acid Biosynthesis
作者:Palash Bhar、Darwin W. Reed、Patrick S. Covello、Peter H. Buist
DOI:10.1002/anie.201202080
日期:2012.7.2
Variations on an oxidative theme: The precision with which FAD2‐type desaturases carry out CH activation reactions on flexible lipidic substrates is astonishing. The conformational space available within the active site of these enzymes has been explored using deuterium‐labeled substrates, and evidence for a novel quasi‐eclipsed conformer has been uncovered. The scheme shows some prototypical substrate
of the deuterated (Z)-11-hexadecenoic acid probes required to decipher the cryptoregiochemistry of this enzyme. The label in the olefinic bonds was introduced by Wittig reaction between the appropriate deuterated reagents. Besides the vinyl deuterium atoms, for reliable GC−MS analyses these compounds bear a tetradeuterium tag, which was introduced by deuteration of an alkyne intermediate in the presence
LC‐MS analysis revealed that in the red phenotype the production of the prodigiosins, undecylprodigiosin and streptorubin B, was strongly induced and, in addition, several intense signals appeared in the LC‐MS chromatogram. Using LC‐MS/MS and NMR spectroscopy, two new prodigiosin derivatives were identified, that is, coeligiosin A and B, which contained an additional undecylpyrrolyl side chain attached
Coelicolor M145链霉菌细菌对过渡金属离子胁迫具有多种生长反应,导致不同的表型。特别是在存在Co 2+离子(0.7 m M)的情况下,天蓝色链霉菌始终产生红色表型。与野生型相比,该表型在挥发性化合物以及高分子量次生代谢产物的产生方面有很大差异。LC-MS分析显示,在红色表型中,强烈诱导了原黄酮素,十一烷基原黄酮素和链霉菌素B的产生,此外,LC-MS色谱图中还出现了一些强烈的信号。使用LC-MS / MS和NMR光谱法,鉴定出了两种新的prodigiosin衍生物,即腔肠球菌素A和B,其中包含一个附加的十一烷基吡咯烷基侧链,连接到十一烷基prodigiosin或链霉菌素B的三吡咯环系统的中心碳上。
Raman spectroscopy of n-pentyl methyl ether and deuterium labelled analogues
作者:Richard D. Bowen、Howell G. M. Edwards、Dennis W. Farwell、Sara E Morgan