Abstract
Earth’s biota produces vast quantities of polymerized silica at ambient temperatures and pressures by mechanisms that are not understood. Silica spicules constitute 75% of the dry weight of the sponge Tethya aurantia, making this organism uniquely tractable for analyses of the proteins intimately associated with the biosilica. Each spicule contains a central protein filament, shown by x-ray diffraction to exhibit a highly regular, repeating structure. The protein filaments can be dissociated to yield three similar subunits, named silicatein α, β, and γ. The molecular weights and amino acid compositions of the three silicateins are similar, suggesting that they are members of a single protein family. The cDNA sequence of silicatein α, the most abundant of these subunits, reveals that this protein is highly similar to members of the cathepsin L and papain family of proteases. The cysteine at the active site in the proteases is replaced by serine in silicatein α, although the six cysteines that form disulfide bridges in the proteases are conserved. Silicatein α also contains unique tandem arrays of multiple hydroxyls. These structural features may help explain the mechanism of biosilicification and the recently discovered activity of the silicateins in promoting the condensation of silica and organically modified siloxane polymers (silicones) from the corresponding silicon alkoxides. They suggest the possibility of a dynamic role of the silicateins in silicification of the sponge spicule and offer the prospect of a new synthetic route to silica and siloxane polymers at low temperature and pressure and neutral pH.
References
35
Referenced
647
-
H A Lowenstam Science 211, 1126–1131 (1981).
(
10.1126/science.7008198) / Science by Lowenstam H A (1981) -
, eds T L Simpson, B E Volcani (Springer, New York Silicon and Siliceous Structures in Biological Systems, 1981).
(
10.1007/978-1-4612-5944-2) / Silicon and Siliceous Structures in Biological Systems by Simpson T L (1981) - M G Voronkov, G I Zelchan, E J Lukevits Silicon and Life (Zinatne, 2nd Ed., Riga, Latvia, 1977). / Silicon and Life by Voronkov M G (1977)
-
R E Hecky, K Mopper, P Kilham, E T Degens Mar Biol 19, 323–331 (1973).
(
10.1007/BF00348902) / Mar Biol by Hecky R E (1973) -
D M Swift, A P Wheeler J Phycol 28, 202–209 (1992).
(
10.1111/j.0022-3646.1992.00202.x) / J Phycol by Swift D M (1992) -
N Kröger, C Bergsdorf, M Sumper EMBO J 13, 4676–4683 (1994).
(
10.1002/j.1460-2075.1994.tb06791.x) / EMBO J by Kröger N (1994) -
C C Harrison Phytochemistry 41, 37–42 (1996).
(
10.1016/0031-9422(95)00576-5) / Phytochemistry by Harrison C C (1996) - K Schwarz Biochemistry of Silicon and Related Problems, eds G Bendz, I Lindqvist (Plenum, New York), pp. 207–230 (1977). / Biochemistry of Silicon and Related Problems by Schwarz K (1977)
-
S Mann Science 261, 1286–1292 (1993).
(
10.1126/science.261.5126.1286) / Science by Mann S (1993) -
C C Harrison, N Loton J Chem Soc Faraday Trans 91, 4287–4297 (1995).
(
10.1039/FT9959104287) / J Chem Soc Faraday Trans by Harrison C C (1995) -
A Firouzi, D, Kumar, M Bull, T Besier, P Sieger, Q Hyo, S A Walker, J A Zasadzinski, C Glinka, J Nicol, et al. Science 267, 1138–1143 (1995).
(
10.1126/science.7855591) / Science by Firouzi A (1995) - S Mann Biomimetic Materials Chemistry, ed S Mann (VCH, New York), pp. 1–40 (1996). / Biomimetic Materials Chemistry by Mann S (1996)
- L T Kuhn, D J Fink, A H Heuer Biomimetic Materials Chemistry, ed S Mann (VCH, New York), pp. 41–68 (1996). / Biomimetic Materials Chemistry by Kuhn L T (1996)
- I A Aksay, J T Staley, R K Prud’homme Biomimetic Materials Chemistry, ed S Mann (VCH, New York), pp. 361–378 (1996). / Biomimetic Materials Chemistry by Aksay I A (1996)
-
T L Simpson The Cell Biology of Sponges (Springer, New York, 1984).
(
10.1007/978-1-4612-5214-6) / The Cell Biology of Sponges by Simpson T L (1984) - R Garrone Phylogenesis of Connective Tissue (Karger, Basel), pp. 176–179 (1978). / Phylogenesis of Connective Tissue by Garrone R (1978)
-
G Imsiecke, R Steffen, M Custodio, R Borojevic, W E G Müller In Vitro Cell Dev Biol 31, 528–535 (1995).
(
10.1007/BF02634030) / In Vitro Cell Dev Biol by Imsiecke G (1995) -
U K Laemli Nature (London) 227, 680–685 (1970).
(
10.1038/227680a0) / Nature (London) by Laemli U K (1970) -
H Towbin, T Staehelin, J Gordon Proc Natl Acad Sci USA 76, 4350–4354 (1979).
(
10.1073/pnas.76.9.4350) / Proc Natl Acad Sci USA by Towbin H (1979) -
A Cornish-Bowden Methods Enzymol 91, 60–75 (1983).
(
10.1016/S0076-6879(83)91011-X) / Methods Enzymol by Cornish-Bowden A (1983) -
C Lee, A Levin, D Branton Anal Biochem 166, 308–312 (1987).
(
10.1016/0003-2697(87)90579-3) / Anal Biochem by Lee C (1987) -
M A Frohman, M K Dush, G R Martin Proc Natl Acad Sci USA 85, 8998–9002 (1988).
(
10.1073/pnas.85.23.8998) / Proc Natl Acad Sci USA by Frohman M A (1988) -
F S Sanger, S Nicklen, A R Coulson Proc Natl Acad Sci USA 74, 5463–5467 (1977).
(
10.1073/pnas.74.12.5463) / Proc Natl Acad Sci USA by Sanger F S (1977) -
P J Berti, A C Storer J Mol Biol 246, 273–283 (1995).
(
10.1006/jmbi.1994.0083) / J Mol Biol by Berti P J (1995) - A Krasko, V Gamulin, J Seack, R Steffen, H C Schröder, W E G Müller Mol Mar Biol Biotech 6, 296–307 (1997). / Mol Mar Biol Biotech by Krasko A (1997)
-
H Kirschke, J Langner, B Wiederanders, S Ansorge, P Bohley Eur J Biochem 74, 293–301 (1977).
(
10.1111/j.1432-1033.1977.tb11393.x) / Eur J Biochem by Kirschke H (1977) -
R Coulombe, P Grochulski, J Sivaraman, R Ménard, J S Mort, M Cygler EMBO J 15, 5492–5503 (1996).
(
10.1002/j.1460-2075.1996.tb00934.x) / EMBO J by Coulombe R (1996) -
C C Perry, Y Lu J Chem Soc Faraday Trans 88, 2915–2921 (1992).
(
10.1039/ft9928802915) / J Chem Soc Faraday Trans by Perry C C (1992) -
N Kröger, G Lehmann, R Rachel, M Sumper Eur J Biochem 250, 99–105 (1997).
(
10.1111/j.1432-1033.1997.00099.x) / Eur J Biochem by Kröger N (1997) -
K D Lobel, J K West, L L Hench Mar Biol 126, 353–360 (1996).
(
10.1007/BF00354617) / Mar Biol by Lobel K D (1996) -
M Hildebrand, B E Volcani, W Gassmann, J I Schroeder Nature (London) 385, 688–689 (1997).
(
10.1038/385688b0) / Nature (London) by Hildebrand M (1997) -
P Bhattacharyya, B E Volcani Biochem Biophys Res Commun 114, 365–372 (1983).
(
10.1016/0006-291X(83)91636-4) / Biochem Biophys Res Commun by Bhattacharyya P (1983) - C C Perry Biomineralization: Chemical and Biochemical Perspectives, eds S Mann, J Webb, R J P Williams (VCH, Weinheim, Germany), pp. 223–256 (1989). / Biomineralization: Chemical and Biochemical Perspectives by Perry C C (1989)
- A Weiss, A Herzog Biochemistry of Silicon and Related Problems, eds G Bendz, I Lindqvist (Plenum, New York), pp. 109–128 (1977). / Biochemistry of Silicon and Related Problems by Weiss A (1977)
- M G Voronkov Biochemistry of Silicon and Related Problems, eds G Bendz, I Lindqvist (Plenum, New York), pp. 395–434 (1977). / Biochemistry of Silicon and Related Problems by Voronkov M G (1977)
Dates
| Type | When |
|---|---|
| Created | 23 years ago (July 26, 2002, 10:42 a.m.) |
| Deposited | 3 years, 2 months ago (June 6, 2022, 9:25 p.m.) |
| Indexed | 1 month ago (July 22, 2025, 7:19 a.m.) |
| Issued | 27 years, 2 months ago (May 26, 1998) |
| Published | 27 years, 2 months ago (May 26, 1998) |
| Published Online | 27 years, 2 months ago (May 26, 1998) |
| Published Print | 27 years, 2 months ago (May 26, 1998) |
@article{Shimizu_1998, title={Silicatein α: Cathepsin L-like protein in sponge biosilica}, volume={95}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.95.11.6234}, DOI={10.1073/pnas.95.11.6234}, number={11}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Shimizu, Katsuhiko and Cha, Jennifer and Stucky, Galen D. and Morse, Daniel E.}, year={1998}, month=may, pages={6234–6238} }