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Biomimetic magnetite formation: from biocombinatorial approaches to mineralization effects.

Baumgartner J, Carillo MA, Eckes KM, Werner P, Faivre D - Langmuir (2014)

Bottom Line: Our results suggest that the identified proteins and biomimetic polypeptides influence nucleation in vitro.Even though the in vivo role cannot be directly determined from our experiments, we can rationalize the following design principles: proteins, larger complexes, or membrane components that promote nucleation in vivo are likely to expose positively charged residues to a negatively charged crystal surface.In turn, components with acidic (negatively charged) functionality are nucleation inhibitors, which stabilize an amorphous structure through the coordination of iron.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces , Science Park Golm, 14424 Potsdam, Germany.

ABSTRACT
Biological materials typically display complex morphologies and hierarchical architectures, properties that are hardly matched by synthetic materials. Understanding the biological control of mineral properties will enable the development of new synthetic approaches toward biomimetic functional materials. Here, we combine biocombinatorial approaches with a proteome homology search and in vitro mineralization assays to assess the role of biological determinants in biomimetic magnetite mineralization. Our results suggest that the identified proteins and biomimetic polypeptides influence nucleation in vitro. Even though the in vivo role cannot be directly determined from our experiments, we can rationalize the following design principles: proteins, larger complexes, or membrane components that promote nucleation in vivo are likely to expose positively charged residues to a negatively charged crystal surface. In turn, components with acidic (negatively charged) functionality are nucleation inhibitors, which stabilize an amorphous structure through the coordination of iron.

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Precipitation products in the presence of peptide polymer and proteinadditives. (A–C) Magnetite particles formed in the presenceof poly-l-arginine. (Insets in C) FFTs of particles indexedas magnetite. (D) SDS-PAGE of MamJ. (E) Precipitation product in thepresence of MamJ. (Inset in E) Electron diffraction reveals only amorphousscattering. (F) SDS-PAGE of MtxAΔ1–24. (G)Precipitation product in the presence of MtxAΔ1–24. (Inset in G) Electron diffraction shows diffraction consistentwith magnetite.
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fig2: Precipitation products in the presence of peptide polymer and proteinadditives. (A–C) Magnetite particles formed in the presenceof poly-l-arginine. (Insets in C) FFTs of particles indexedas magnetite. (D) SDS-PAGE of MamJ. (E) Precipitation product in thepresence of MamJ. (Inset in E) Electron diffraction reveals only amorphousscattering. (F) SDS-PAGE of MtxAΔ1–24. (G)Precipitation product in the presence of MtxAΔ1–24. (Inset in G) Electron diffraction shows diffraction consistentwith magnetite.

Mentions: We studied the influence of the selected proteins (MamJ and MtxAΔ1–24) as well as the two peptide polymers poly-l-arginine (polyR) and poly-l-glutamic acid (polyE)on magnetite formation. Apart from structural differences, the proteins/polymersdiffer primarily in the availability of differently charged groupsthat can interact with different iron or iron (oxyhydr)oxide species.Acid residues in MamJ and polyE provide binding moieties for cationicFeII/III, whereas the cationic guanidinium group of polyRis able to interact electrostatically with (in alkaline solution)negatively charged iron (oxyhydr)oxide crystal surfaces. The presenceof the additives has a strong effect on the phase, crystallinity,particle size, morphology, and aggregation of the precipitates, inagreement with the interactions with soluble or solid iron speciesthat occur either prior to or after the nucleation of the magnetitephase (Figures 2–4).


Biomimetic magnetite formation: from biocombinatorial approaches to mineralization effects.

Baumgartner J, Carillo MA, Eckes KM, Werner P, Faivre D - Langmuir (2014)

Precipitation products in the presence of peptide polymer and proteinadditives. (A–C) Magnetite particles formed in the presenceof poly-l-arginine. (Insets in C) FFTs of particles indexedas magnetite. (D) SDS-PAGE of MamJ. (E) Precipitation product in thepresence of MamJ. (Inset in E) Electron diffraction reveals only amorphousscattering. (F) SDS-PAGE of MtxAΔ1–24. (G)Precipitation product in the presence of MtxAΔ1–24. (Inset in G) Electron diffraction shows diffraction consistentwith magnetite.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3958130&req=5

fig2: Precipitation products in the presence of peptide polymer and proteinadditives. (A–C) Magnetite particles formed in the presenceof poly-l-arginine. (Insets in C) FFTs of particles indexedas magnetite. (D) SDS-PAGE of MamJ. (E) Precipitation product in thepresence of MamJ. (Inset in E) Electron diffraction reveals only amorphousscattering. (F) SDS-PAGE of MtxAΔ1–24. (G)Precipitation product in the presence of MtxAΔ1–24. (Inset in G) Electron diffraction shows diffraction consistentwith magnetite.
Mentions: We studied the influence of the selected proteins (MamJ and MtxAΔ1–24) as well as the two peptide polymers poly-l-arginine (polyR) and poly-l-glutamic acid (polyE)on magnetite formation. Apart from structural differences, the proteins/polymersdiffer primarily in the availability of differently charged groupsthat can interact with different iron or iron (oxyhydr)oxide species.Acid residues in MamJ and polyE provide binding moieties for cationicFeII/III, whereas the cationic guanidinium group of polyRis able to interact electrostatically with (in alkaline solution)negatively charged iron (oxyhydr)oxide crystal surfaces. The presenceof the additives has a strong effect on the phase, crystallinity,particle size, morphology, and aggregation of the precipitates, inagreement with the interactions with soluble or solid iron speciesthat occur either prior to or after the nucleation of the magnetitephase (Figures 2–4).

Bottom Line: Our results suggest that the identified proteins and biomimetic polypeptides influence nucleation in vitro.Even though the in vivo role cannot be directly determined from our experiments, we can rationalize the following design principles: proteins, larger complexes, or membrane components that promote nucleation in vivo are likely to expose positively charged residues to a negatively charged crystal surface.In turn, components with acidic (negatively charged) functionality are nucleation inhibitors, which stabilize an amorphous structure through the coordination of iron.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomaterials, Max Planck Institute of Colloids and Interfaces , Science Park Golm, 14424 Potsdam, Germany.

ABSTRACT
Biological materials typically display complex morphologies and hierarchical architectures, properties that are hardly matched by synthetic materials. Understanding the biological control of mineral properties will enable the development of new synthetic approaches toward biomimetic functional materials. Here, we combine biocombinatorial approaches with a proteome homology search and in vitro mineralization assays to assess the role of biological determinants in biomimetic magnetite mineralization. Our results suggest that the identified proteins and biomimetic polypeptides influence nucleation in vitro. Even though the in vivo role cannot be directly determined from our experiments, we can rationalize the following design principles: proteins, larger complexes, or membrane components that promote nucleation in vivo are likely to expose positively charged residues to a negatively charged crystal surface. In turn, components with acidic (negatively charged) functionality are nucleation inhibitors, which stabilize an amorphous structure through the coordination of iron.

Show MeSH