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Hemocyanins are large oligomeric copper-containing pro-teins that serve for the transport of oxygen in many arth-ropod species. While studied in detail in the Chelicerata and Crustacea, hemocyanins had long been considered unnec-essary in the Myriapoda. Here we report the complete molecular structure of the hemocyanin from the common house centipedeScutigera coleoptrata(Myriapoda: Chilo-poda), as deduced from 2D-gel electrophoresis, MALDI-TOF mass spectrometry, protein and cDNA sequencing, and homology modeling | Eur. J. Biochem. 270 2860-2868 2003 FEBS 2003 doi 10.1046 j.1432-1033.2003.03664.x Complete subunit sequences structure and evolution of the 6 X 6-mer hemocyanin from the common house centipede Scutigera coleoptrata Kristina Kusche Anne Hembach Silke Hagner-Holler Wolfgang Gebauer and Thorsten Burmester Institute of Zoology Molecular Animal Physiology University of Mainz Germany Hemocyanins are large oligomeric copper-containing proteins that serve for the transport of oxygen in many arthropod species. While studied in detail in the Chelicerata and Crustacea hemocyanins had long been considered unnecessary in the Myriapoda. Here we report the complete molecular structure of the hemocyanin from the common house centipede Scutigera coleoptrata Myriapoda Chilo-poda as deduced from 2D-gel electrophoresis MALDI-TOF mass spectrometry protein and cDNA sequencing and homology modeling. This is the first myriapod hemocyanin to be fully sequenced and allows the investigation of hemocyanin structure-function relationship and evolution. S. coleoptrata hemocyanin is a 6 X 6-mer composed of four distinct subunit types that occur in an approximate 2 2 1 1 ratio and are 49.5-55.5 identical. The cDNA of a fifth highly diverged putative hemocyanin was identified that is not included in the native 6 X 6-mer hemocyanin. Phylogenetic analyses show that myriapod hemocyanins are monophyletic but at least three distinct subunit types evolved before the separation of the Chilo-poda and Diplopoda more than 420 million years ago. In contrast to the situation in the Crustacea and Chelicerata the substitution rates among the myriapod hemocyanin subunits are highly variable. Phylogenetic analyses do not support a common clade of Myriapoda and Hexapoda whereas there is evidence in favor of monophyletic Mandibulata. Keywords hemocyanin subunit diversity structure Arthro-poda evolution. Oxygen transport in the body fluid of many arthropod and molluscan species is mediated by large .
