State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P.R. China.
Sci Rep. 2013;3:1753. doi: 10.1038/srep01753.
For biosynthesis of bacillamide C by Bacillus atrophaeus C89 associated with South China sea sponge Dysidea avara, it is hypothesized that decarboxylation from L-tryptophan to tryptamine could be performed before amidation by the downstream aromatic L-amino acid decarboxylase (AADC) to the non-ribosomal peptide synthetases (NRPS) gene cluster for biosynthesizing bacillamide C. The structural analysis of decarboxylases' known substrates in KEGG database and alignment analysis of amino acid sequence of AADC have suggested that L-tryptophan and L-phenylalanine are the potential substrates of AADC. The enzymatic kinetic experiment of the recombinant AADC proved that L-tryptophan is a more reactive substrate of AADC than L-phenylalanine. Meanwhile, the AADC-catalyzed conversion of L-tryptophan into tryptamine was confirmed by means of HPLC and LC/MS. Thus during bacillamide C biosynthesis, the decarboxylation of L-tryptophan to tryptamine is likely conducted first under AADC catalysis, followed by the amidation of tryptamine with the carboxylic product of NRPS gene cluster.
对于南海海绵 Dysidea avara 相关的萎缩芽孢杆菌 C89 生物合成杆菌酰胺 C，假设在通过下游芳香族 L-氨基酸脱羧酶（AADC）进行酰胺化之前，L-色氨酸可以脱羧生成色胺，然后再由非核糖体肽合成酶（NRPS）基因簇生物合成杆菌酰胺 C。KEGG 数据库中已知脱羧酶底物的结构分析和 AADC 氨基酸序列比对分析表明，L-色氨酸和 L-苯丙氨酸可能是 AADC 的底物。重组 AADC 的酶动力学实验证明，L-色氨酸是 AADC 的比 L-苯丙氨酸更具反应性的底物。同时，通过 HPLC 和 LC/MS 证实了 AADC 催化的 L-色氨酸转化为色胺。因此，在杆菌酰胺 C 生物合成过程中，L-色氨酸的脱羧反应可能首先在 AADC 催化下进行，然后与 NRPS 基因簇的羧酸产物进行色胺的酰胺化。
