Biotechnological Mineral Composites via Vaterite Precursors
- PDF / 2,924,248 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 70 Downloads / 153 Views
Biotechnological Mineral Composites via Vaterite Precursors E. Weber1, 2, C. Guth1, M. Eder1, P. Bauer2, E. Arzt3 and I. M. Weiss1,* INM – Leibniz Institute for New Materials gGmbH, Biomineralization Group, Campus D2.2, D-66123 Saarbruecken, Germany; *Correspondence: [email protected] 2 Saarland University, Department Biosciences – Plant Biology, Campus A2.4, D-66123 Saarbruecken, Germany 3 INM – Leibniz Institute for New Materials gGmbH, Functional Surfaces Group, Campus D2.2, D-66123 Saarbruecken, Germany
1
ABSTRACT Vaterite is one of the thermodynamically less stable polymorphs of calcium carbonate. Under ambient conditions it transforms into calcite, the most stable form of calcium carbonate. Organisms are able to stabilize minerals such as vaterite by means of organic molecules. The exact mechanisms how biomineralization proteins interact with metastable mineral phases are, however, less well understood. Many in vitro studies were performed using calcite as a model system. A deeper understanding of the interaction of organic molecules with metastable mineral phases would make them useful as a tool to control mineralization processes in vitro. In this study, we report on the co-precipitation of a natively soluble histidine-tagged GFP (green fluorecent protein) with a metastable vaterite phase and the subsequent insolubility of the fluorescent organic matrix in a 30µl calcium carbonate precipitation assay. The intrinsic fluorescence of GFP is conserved during the interaction with the mineral phase, indicating proper folding even in the insoluble state. This experiment can be extended to obtain deeper insights into some mechanistic models of biomineralization proteins by tracking native and modified GFP proteins microscopically during various stages of mineral precipitation and dissolution. INTRODUCTION Biomineralization is one of the most fascinating processes in nature to generate biocomposite materials with extraordinary properties [1]. In particular, mollusc shells have gained attraction due to their different calcium carbonate polymorphs. The control over mineral polymorphs such as calcite, vaterite and aragonite was also demonstrated in vitro to be influenced by extracts from specific shell regions [2, 3]. Non-biogenic vaterite likely transforms into aragonite and calcite under ambient conditions [4, 5]. Some organisms produce stable vaterite [1, 6, 7], for example the freshwater bivalve Corbicula fluminea [8, 9]. Even the pure presence of extracted biomineralization proteins, for example the 28kDa EP protein from Mytilus edulis, influences the mineral shape and texture of an otherwise unstable mineral phase in microfluidics with defined geometries and ionic composition [10]. Pokroy and colleagues used the 40kDa protein from the aragonitic crossed-lamellar shell of Strombus decorus persicus in concentrations of 40µg/ml to produced vaterite crystals of 50-100µm dimensions [11]. In this study, we used a recombinant 6×histidine tagged-GFP (green fluorescent protein) produced in E. coli and demonstrated
Data Loading...
