Structure, diversity and evolution of myriapod hemocyanins
Structure, diversity and evolution of myriapod hemocyanins
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多足类血蓝蛋白的结构、多样性和进化
DOI：
10.1111/febs.12742
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Burmester
中科院分区：
文献类型：
--
作者：
Scherbaum;Hegedüs;Neumann;Burmester
许多节肢动物血淋巴中的氧转运是由血蓝蛋白介导的，血蓝蛋白是一种大型含铜蛋白质，在螯肢动物和甲壳动物中得到了很好的研究，但长期以来一直被认为是多足动物亚门中不必要的。直到最近才发现血蓝蛋白存在于Scutigeromorpha（唇足目）和Spirostreptida（倍足目）中。在这里，我们提出了一个更广泛的发生在多足类血蓝蛋白的证据。通过RT-PCR、Western blotting和数据库检索，在综合门Hanseniella audax和Symphylella vulgaris、唇足蜈蚣Scolopendra subspinipes dehaani和二倍体蜈蚣Polydesmus angustus中鉴定了血蓝蛋白。在兔尾多爪螨、斑点多爪螨、缘球囊霉、脓疱球囊霉和布氏关节球腔菌中，以及在唇足类类中未发现血蓝蛋白。这表明多足动物类群中有多个独立的损失。两个独立的血蓝蛋白亚基被发现，已经存在于多足类干细胞系。我们专门研究了血蓝蛋白的结构ofP. angustus，它由三个不同的亚基，发生在一个近似等摩尔比。通过3D电子显微镜推断，四级结构是3 × 6-mer，类似于Scutigera coleoptrata的6 × 6-mer血蓝蛋白的半结构。通过1 × 6-mer的同源建模及其与3 × 6-mer电子密度图的刚体拟合对其进行了更密切的分析。此外，我们获得了一个假定的多足类酚氧化酶的cDNA序列。酚氧化酶与节肢动物血蓝蛋白有关，但在节肢动物亚门辐射前已分化。
Oxygen transport in the hemolymph of many arthropods is mediated by hemocyanins, large copper‐containing proteins that are well‐studied in Chelicerata and Crustacea, but had long been considered unnecessary in the subphylum of Myriapoda. Only recently has it become evident that hemocyanins are present in Scutigeromorpha (Chilopoda) and Spirostreptida (Diplopoda). Here we present evidence for a more widespread occurrence of hemocyanin in the myriapods. By means of RT‐PCR, western blotting and database searches, hemocyanins were identified in the symphylansHanseniella audaxandSymphylella vulgaris, the chilopodScolopendra subspinipes dehaaniand the diplopodPolydesmus angustus. No hemocyanins were found in the diplopodsPolyxenus lagurus,Cylindroiulus punctatus,Glomeris marginata,Glomeris pustulataandArthrosphaera brandtii, or the chilopodsLithobius forficatus,Geophilus flavusandStrigamia maritima. This suggests multiple independent losses in myriapod taxa. Two independent hemocyanin subunits were found that were already present in the myriapod stem line. We specifically investigated the structure of the hemocyanin ofP. angustus, which consists of three distinct subunits that occur in an approximately equimolar ratio. As deduced by 3D electron microscopy, the quaternary structure is a 3 × 6‐mer that resembles the half structure of the 6 × 6‐mer hemocyanin fromScutigera coleoptrata. It was analyzed more closely by homology modeling of 1 × 6‐mers and their rigid‐body fitting to the electron density map of the 3 × 6‐mer. In addition, we obtained the cDNA sequence of a putative myriapod phenoloxidase. Phenoloxidases are related to the arthropod hemocyanins, but diverged before radiation of the arthropod subphyla.