bm_147.pdf 235 KB
Shimizu, Katsuhiko Platform for Community-Based Research and Education, Tottori University Researchers DB KAKEN
Kobayashi, Hiroki The United Graduate School of Agricultural Sciences, Tottori University
Nishi, Michika Faculty of Agriculture, Tottori University
Tsukahara, Masatoshi BioJet Ltd
Bito, Tomohiro Faculty of Agriculture, Tottori University Researchers DB KAKEN
Arima, Jiro Faculty of Agriculture, Tottori University Researchers DB KAKEN
Silicatein is the first protein isolated from the silicon biominerals and characterized as constituent of the axial filament in the silica spicules of the demosponge Tethya aurantia, by significant sequence similarity with cathepsin L, an animal lysosomal protease, and as a catalyst of silica polycondensation at neutral pH and room temperature. This protein was then identified in a wide range of the class Demospongiae and in some species of the class Hexactinellida. Our attempt to isolate silicatein from the silica skeleton of Euplectella was unsuccessful, but instead we discovered glassin, a protein directing acceleration of silica polycondensation and sharing no significant relationship with any proteins including silicatein. The present study aims to verify the existence of silicatein by exploring the whole genome DNA sequence database of E. curvistellata with the sequence similarity search. Although we identified the sequences of glassin, cathepsin L and chitin synthetase, an enzyme synthesizing chitin, which has already been found in the silicon biominerals in E. aspergillum, silicatein failed to be identified. Our result indicates that silicatein is not essential for poriferan silicon biomineralization in the presence of glassin.
(C) The Author(s) 2018. This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The images or other third party material in this chapter are included in the chapter’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
Shimizu, K., Kobayashi, H., Nishi, M., Tsukahara, M., Bito, T., Arima, J. (2018). Exploration of Genes Associated with Sponge Silicon Biomineralization in the Whole Genome Sequence of the Hexactinellid Euplectella curvistellata . In: Endo, K., Kogure, T., Nagasawa, H. (eds) Biomineralization. Springer, Singapore. https://doi.org/10.1007/978-981-13-1002-7_16