title: Silicateins--a novel paradigm in bioinorganic chemistry: enzymatic synthesis of inorganic polymeric silica.
abstract: The inorganic matrix of the siliceous skeletal elements of sponges, that is, spicules, is formed of amorphous biosilica. Until a decade ago, it remained unclear how the hard biosilica monoliths of the spicules are formed in sponges that live in a silica-poor (<50 μM) aquatic environment. The following two discoveries caused a paradigm shift and allowed an elucidation of the processes underlying spicule formation; first the discovery that in the spicules only one major protein, silicatein, exists and second, that this protein displays a bio-catalytical, enzymatic function. These findings caused a paradigm shift, since silicatein is the first enzyme that catalyzes the formation of an inorganic polymer from an inorganic monomeric substrate. In the present review the successive steps, following the synthesis of the silicatein product, biosilica, and resulting in the formation of the hard monolithic spicules is given. The new insight is assumed to open new horizons in the field of biotechnology and also in biomedicine.
authors.affiliation: ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany. wmueller@uni-mainz.de
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.forename: Zaklina
authors.initials: Z
authors.lastname: Burghard
authors.forename: Dario
authors.initials: D
authors.lastname: Pisignano
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D055162:Biocatalysis; D002119:Calcium Carbonate / Q000737:chemistry*; D002384:Catalysis; D002403:Cathepsins / Q000737:chemistry* / Q000378:metabolism; D015393:Chemistry, Bioinorganic; D011108:Polymers / Q000737:chemistry*; D011161:Porifera / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D017640:Silicates / Q000737:chemistry*; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D047233:Suberites / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism
chemical_list: D011108:Polymers; D017640:Silicates; D012822:Silicon Dioxide; D002403:Cathepsins; D002119:Calcium Carbonate