Puddick Jonathan, Prinsep Michèle R, Wood Susanna A, Cary Stephen Craig, Hamilton David P, Holland Patrick T
Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
Department of Chemistry, School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
Toxins (Basel). 2015 Feb 10;7(2):493-515. doi: 10.3390/toxins7020493.
Microcystins are hepatotoxic cyclic peptides produced by several cyanobacterial genera worldwide. In 2008, our research group identified eight new glycine-containing microcystin congeners in two hydro-terrestrial mat samples from the McMurdo Dry Valleys of Eastern Antarctica. During the present study, high-resolution mass spectrometry, amino acid analysis and micro-scale thiol derivatization were used to further elucidate their structures. The Antarctic microcystin congeners contained the rare substitution of the position-1 ᴅ-alanine for glycine, as well as the acetyl desmethyl modification of the position-5 Adda moiety (3S-amino-9S-methoxy-2S,6,8S-trimethyl-10-phenyldeca-4E,6E-dienoic acid). Amino acid analysis was used to determine the stereochemistry of several of the amino acids and conclusively demonstrated the presence of glycine in the microcystins. A recently developed thiol derivatization technique showed that each microcystin contained dehydrobutyrine in position-7 instead of the commonly observed N-methyl dehydroalanine.
微囊藻毒素是由全球多个蓝藻属产生的具有肝毒性的环肽。2008年，我们的研究小组在来自东南极麦克默多干谷的两个水陆交错带样本中鉴定出了8种新的含甘氨酸微囊藻毒素同系物。在本研究中，使用高分辨率质谱、氨基酸分析和微量硫醇衍生化来进一步阐明它们的结构。南极微囊藻毒素同系物含有1位的甘氨酸对罕见的ᴅ-丙氨酸的取代，以及5位Adda部分（3S-氨基-9S-甲氧基-2S,6,8S-三甲基-10-苯基癸-4E,6E-二烯酸）的乙酰去甲基修饰。氨基酸分析用于确定几种氨基酸的立体化学，并最终证明微囊藻毒素中存在甘氨酸。最近开发的硫醇衍生化技术表明，每种微囊藻毒素在7位含有脱氢丁氨酸，而不是常见的N-甲基脱氢丙氨酸。
