两类藻毒素聚酮合成酶遗传相似性及其二级结构预测分析

研究微囊藻毒素聚酮合成酶、节球藻毒素聚酮合成酶之间的遗传关联性,并对其二级结构进行预测分析.应用聚合酶链反应得到2株蓝绿藻的毒素聚酮合成酶(PKS)基因,并进行基因序列分析.从GenBank中提取产微囊藻毒素、产节球藻毒素藻株的相应基因序列,利用DNAStar和phylip软件分析目的基因一致性及2类藻毒素PKS的进化情况.采用Garnier-Robson法、Karplus-Schulz法预测项圈藻株202A1/35、节球藻株NSOR10PKS蛋白片段的二级结构,Kyte-doolittle法分析蛋白的亲水性,Emini法预测蛋白质的表面可能性.结果表明,2类藻毒素PKS目的基因的相似性非常高;项圈藻属、念珠藻属的微囊藻毒素PKS与节球藻毒素PKS的进化关系较近;2种藻毒素PKS分析片段二级结构具有较大的相似性,其亲水性与表面可能性区域等特征也极为相似.

Genetic similarity and secondary structure prediction of two cyanobacterial toxins'polyketide synthetases

to investigate the genetic similarity and secondary structure prediction of polyketide synthetases corresponding to microcystins and nodularins, respectively. Gene of polyketide synthase (PKS) from 2 toxin-producing cyanobacteria was prepared by polymerase chain reaction and the gene sequence was analyzed. The gene sequences of PKS from microcystins-producing cyanobacteria and nodularins-producing ones were derived from GenBank. Their sequence identity and phylogenetic similarity of corresponding proteins was analyzed using the software of both DNAStar and phylip. The secondary structure of PKS of Anabaena sp. 202A1/35 and Nodularia spumigena NSOR10 was predicted using the methods of Garnier-Robson and Karplus-Schulz. The Hydrophilic plot and surface probability plot were obtained from Kyte-doolittle and Emini, respectively. The results indicate that the target gene sequences for both microcystin PKS and nodularin PKS share high identity; Phylogenetic analysis suggests close phylogenetic relationships between Anabaena sp., Nostoc sp. and Nodularia sp. There are significant similarities in the secondary structure of the analyzed proteins. Both PKS show similar identical hydrophilicity and surface probability characteristics.