Limits...
Self-assembly and modular functionalization of three-dimensional crystals from oppositely charged proteins.

Liljeström V, Mikkilä J, Kostiainen MA - Nat Commun (2014)

Bottom Line: Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment.Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules.Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range.

View Article: PubMed Central - PubMed

Affiliation: 1] Biohybrid Materials Group, Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland [2] Molecular Materials Group, Department of Applied Physics, Aalto University, 00076 Aalto, Finland.

ABSTRACT
Multicomponent crystals and nanoparticle superlattices are a powerful approach to integrate different materials into ordered nanostructures. Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment. Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules. We electrostatically assembled cowpea chlorotic mottle virus particles and avidin proteins into heterogeneous crystals, where the virus particles adopt a non-close-packed body-centred cubic arrangement held together by avidin. Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range. Furthermore, the use of avidin-biotin interaction allows highly selective pre- or post-functionalization of the protein crystals in a modular way with different types of functional units, such as fluorescent dyes, enzymes and plasmonic nanoparticles.

No MeSH data available.


Related in: MedlinePlus

SAXS and cryo-TEM characterization of binary CCMV–avidin crystals.(a) Integrated and indexed SAXS curve measured from self-assembled CCMV–avidin crystals and comparison with calculated curves. (b) 2D scattering pattern. (c) Quadratic Miller indices of assigned reflections for  structure versus measured q-vector positions for five indexed peaks. Solid line presents a linear fit, which yields a lattice parameter aSAXS=35.0 nm (for cubic phases a=2π✓(h2+k2+l2)/q(hkl)). (d) CCMV–avidin crystal adopts a bcc arrangement (particle size reduced for clarity). (e) Low-magnification view of CCMV–avidin binary crystal in random orientation. Scale bar, 200 nm. (f) Crystal viewed along the [100] projection axis. One unit cell with measured aTEM=35.9 nm is outlined with cyan. Inset shows a fast Fourier transform image. (g) A model unit cell viewed along [100] projection axis. (h) Filtered inverse Fourier transform from selected Fourier components.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4109007&req=5

f3: SAXS and cryo-TEM characterization of binary CCMV–avidin crystals.(a) Integrated and indexed SAXS curve measured from self-assembled CCMV–avidin crystals and comparison with calculated curves. (b) 2D scattering pattern. (c) Quadratic Miller indices of assigned reflections for structure versus measured q-vector positions for five indexed peaks. Solid line presents a linear fit, which yields a lattice parameter aSAXS=35.0 nm (for cubic phases a=2π✓(h2+k2+l2)/q(hkl)). (d) CCMV–avidin crystal adopts a bcc arrangement (particle size reduced for clarity). (e) Low-magnification view of CCMV–avidin binary crystal in random orientation. Scale bar, 200 nm. (f) Crystal viewed along the [100] projection axis. One unit cell with measured aTEM=35.9 nm is outlined with cyan. Inset shows a fast Fourier transform image. (g) A model unit cell viewed along [100] projection axis. (h) Filtered inverse Fourier transform from selected Fourier components.

Mentions: Integrated scattering curve measured from aqueous suspension of CCMV–avidin crystals in the presence of 15 mM NaCl shows multiple clear diffraction maxima indicating long range order prevalent in the assemblies (Fig. 3a). The 2D diffraction patterns show multiple Debye rings typical to polycrystalline samples with isotropic orientation of multiple crystals as in powder-like samples (Fig. 3b). The positions of the diffraction peaks in the azimuthally integrated curve are found at q=0.025, 0.036, 0.044, 0.051 and 0.057 Å−1 corresponding to the crystal plane reflections with Miller indices (hkl)=(110), (200), (211), (220) and (310), respectively. The qn/q* ratio follows ✓2:✓4:✓6:✓8:✓10, indicating a cubic lattice. The quadratic Miller indices were plotted against the measured q(hkl) values and fitted with linear regression to obtain the lattice constant a. For cubic phases asaxs=2π✓(h2+k2+l2)/q(hkl), which was determined to be 35.0 nm (Fig. 3c). Based on the positions, widths and the relative intensities of the diffraction maxima, the structure is best described as finite body-centred cubic (bcc) Bravais lattice structure (space group , number 229; Fig. 3d). The crystal structure of CCMV–avidin assemblies obtained from SAXS studies was further verified by cryogenic transmission electron microscopy (cryo-TEM) that supported the bcc crystallographic arrangement. The crystals identified in standard and low-magnification (Supplementary Fig. 3) images were 3D polycrystallites with single-crystal-domain sizes approaching 1 μm (Fig. 3e). An image featuring a crystal viewed along the [100] projection axis shows the expected cubic arrangement (unit cell highlighted in cyan) with a measured lattice constant aTEM=35.9 nm (Fig. 3f–h).


Self-assembly and modular functionalization of three-dimensional crystals from oppositely charged proteins.

Liljeström V, Mikkilä J, Kostiainen MA - Nat Commun (2014)

SAXS and cryo-TEM characterization of binary CCMV–avidin crystals.(a) Integrated and indexed SAXS curve measured from self-assembled CCMV–avidin crystals and comparison with calculated curves. (b) 2D scattering pattern. (c) Quadratic Miller indices of assigned reflections for  structure versus measured q-vector positions for five indexed peaks. Solid line presents a linear fit, which yields a lattice parameter aSAXS=35.0 nm (for cubic phases a=2π✓(h2+k2+l2)/q(hkl)). (d) CCMV–avidin crystal adopts a bcc arrangement (particle size reduced for clarity). (e) Low-magnification view of CCMV–avidin binary crystal in random orientation. Scale bar, 200 nm. (f) Crystal viewed along the [100] projection axis. One unit cell with measured aTEM=35.9 nm is outlined with cyan. Inset shows a fast Fourier transform image. (g) A model unit cell viewed along [100] projection axis. (h) Filtered inverse Fourier transform from selected Fourier components.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109007&req=5

f3: SAXS and cryo-TEM characterization of binary CCMV–avidin crystals.(a) Integrated and indexed SAXS curve measured from self-assembled CCMV–avidin crystals and comparison with calculated curves. (b) 2D scattering pattern. (c) Quadratic Miller indices of assigned reflections for structure versus measured q-vector positions for five indexed peaks. Solid line presents a linear fit, which yields a lattice parameter aSAXS=35.0 nm (for cubic phases a=2π✓(h2+k2+l2)/q(hkl)). (d) CCMV–avidin crystal adopts a bcc arrangement (particle size reduced for clarity). (e) Low-magnification view of CCMV–avidin binary crystal in random orientation. Scale bar, 200 nm. (f) Crystal viewed along the [100] projection axis. One unit cell with measured aTEM=35.9 nm is outlined with cyan. Inset shows a fast Fourier transform image. (g) A model unit cell viewed along [100] projection axis. (h) Filtered inverse Fourier transform from selected Fourier components.
Mentions: Integrated scattering curve measured from aqueous suspension of CCMV–avidin crystals in the presence of 15 mM NaCl shows multiple clear diffraction maxima indicating long range order prevalent in the assemblies (Fig. 3a). The 2D diffraction patterns show multiple Debye rings typical to polycrystalline samples with isotropic orientation of multiple crystals as in powder-like samples (Fig. 3b). The positions of the diffraction peaks in the azimuthally integrated curve are found at q=0.025, 0.036, 0.044, 0.051 and 0.057 Å−1 corresponding to the crystal plane reflections with Miller indices (hkl)=(110), (200), (211), (220) and (310), respectively. The qn/q* ratio follows ✓2:✓4:✓6:✓8:✓10, indicating a cubic lattice. The quadratic Miller indices were plotted against the measured q(hkl) values and fitted with linear regression to obtain the lattice constant a. For cubic phases asaxs=2π✓(h2+k2+l2)/q(hkl), which was determined to be 35.0 nm (Fig. 3c). Based on the positions, widths and the relative intensities of the diffraction maxima, the structure is best described as finite body-centred cubic (bcc) Bravais lattice structure (space group , number 229; Fig. 3d). The crystal structure of CCMV–avidin assemblies obtained from SAXS studies was further verified by cryogenic transmission electron microscopy (cryo-TEM) that supported the bcc crystallographic arrangement. The crystals identified in standard and low-magnification (Supplementary Fig. 3) images were 3D polycrystallites with single-crystal-domain sizes approaching 1 μm (Fig. 3e). An image featuring a crystal viewed along the [100] projection axis shows the expected cubic arrangement (unit cell highlighted in cyan) with a measured lattice constant aTEM=35.9 nm (Fig. 3f–h).

Bottom Line: Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment.Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules.Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range.

View Article: PubMed Central - PubMed

Affiliation: 1] Biohybrid Materials Group, Department of Biotechnology and Chemical Technology, Aalto University, 00076 Aalto, Finland [2] Molecular Materials Group, Department of Applied Physics, Aalto University, 00076 Aalto, Finland.

ABSTRACT
Multicomponent crystals and nanoparticle superlattices are a powerful approach to integrate different materials into ordered nanostructures. Well-developed, especially DNA-based, methods for their preparation exist, yet most techniques concentrate on molecular and synthetic nanoparticle systems in non-biocompatible environment. Here we describe the self-assembly and characterization of binary solids that consist of crystalline arrays of native biomacromolecules. We electrostatically assembled cowpea chlorotic mottle virus particles and avidin proteins into heterogeneous crystals, where the virus particles adopt a non-close-packed body-centred cubic arrangement held together by avidin. Importantly, the whole preparation process takes place at room temperature in a mild aqueous medium allowing the processing of delicate biological building blocks into ordered structures with lattice constants in the nanometre range. Furthermore, the use of avidin-biotin interaction allows highly selective pre- or post-functionalization of the protein crystals in a modular way with different types of functional units, such as fluorescent dyes, enzymes and plasmonic nanoparticles.

No MeSH data available.


Related in: MedlinePlus