Bis Dana M, Ban Yang H, James Elle D, Alqahtani Norah, Viswanathan Rajesh, Lane Amy L
Chemistry Department, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224 (USA).
Chembiochem. 2015 Apr 13;16(6):990-7. doi: 10.1002/cbic.201500007. Epub 2015 Mar 5.
Macrolide-pipecolate natural products, such as rapamycin (1) and FK-506 (2), are renowned modulators of FK506-binding proteins (FKBPs). The nocardiopsins, from Nocardiopsis sp. CMB-M0232, are the newest members of this structural class. Here, the biosynthetic pathway for nocardiopsins A-D (4-7) is revealed by cloning, sequencing, and bioinformatic analyses of the nsn gene cluster. In vitro evaluation of recombinant NsnL revealed that this lysine cyclodeaminase catalyzes the conversion of L-lysine into the L-pipecolic acid incorporated into 4 and 5. Bioinformatic analyses supported the conjecture that a linear nocardiopsin precursor is equipped with the hydroxy group required for macrolide closure in a previously unobserved manner by employing a P450 epoxidase (NsnF) and limonene epoxide hydrolase homologue (NsnG). The nsn cluster also encodes candidates for tetrahydrofuran group biosynthesis. The nocardiopsin pathway provides opportunities for engineering of FKBP-binding metabolites and for probing new enzymology in nature's polyketide tailoring arsenal.
大环内酯 - 哌啶酸天然产物，如雷帕霉素（1）和FK - 506（2），是著名的FK506结合蛋白（FKBPs）调节剂。来自诺卡氏菌属菌株CMB - M0232的杀伤骨菌素是这一结构类别的最新成员。在此，通过对nsn基因簇进行克隆、测序和生物信息学分析，揭示了杀伤骨菌素A - D（4 - 7）的生物合成途径。重组NsnL的体外评估表明，这种赖氨酸环脱氨酶催化L - 赖氨酸转化为并入4和5中的L - 哌啶酸。生物信息学分析支持了这样的推测，即一种线性杀伤骨菌素前体通过使用细胞色素P450环氧化酶（NsnF）和柠檬烯环氧化物水解酶同系物（NsnG），以一种先前未观察到的方式配备了大环内酯环化所需的羟基。nsn基因簇还编码四氢呋喃基团生物合成的候选基因。杀伤骨菌素途径为工程改造FKBP结合代谢物以及探索自然界聚酮化合物修饰库中的新酶学提供了机会。
