Directed Assembly of Discrete Gold Nanoparticle Groupings Using Branched DNA Scaffolds

Claridge, Shelley A.; Goh, Sarah L.; Fréchet, Jean M. J.; Williams, Shara C.; Micheel, Christine; Alivisatos, A. Paul

doi:10.1021/cm0484089

Cited by 144 publications

(141 citation statements)

References 40 publications

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“…DNA-Au nanoparticle conjugates have been used for a variety of purposes, including nanoparticle self-assembly (14) and as probes of biomolecular dynamics (18). For small gold nanoparticles (Ͻ15 nm in diameter) and DNA oligonucleotides longer than 100 bp, it is straightforward to tune the number of DNA molecules attached to each particle (11,12).…”

Section: Discussionmentioning

confidence: 99%

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Protein-Nanocrystal Conjugates Support a Single Filament Polymerization Model in R1 Plasmid Segregation

Choi

Claridge

Garner

et al. 2008

Journal of Biological Chemistry

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To ensure inheritance by daughter cells, many low-copy number bacterial plasmids, including the R1 drug-resistance plasmid, encode their own DNA segregation systems. The par operon of plasmid R1 directs construction of a simple spindle structure that converts free energy of polymerization of an actin-like protein, ParM, into work required to move sister plasmids to opposite poles of rod-shaped cells. The structures of individual components have been solved, but little is known about the ultrastructure of the R1 spindle. To determine the number of ParM filaments in a minimal R1 spindle, we used DNA-gold nanocrystal conjugates as mimics of the R1 plasmid. We found that each end of a single polar ParM filament binds to a single ParR/parC-gold complex, consistent with the idea that ParM filaments bind in the hollow core of the ParR/parC ring complex. Our results further suggest that multifilament spindles observed in vivo are associated with clusters of plasmids segregating as a unit.In eubacteria and archaea, many biologically important processes are carried out by genes encoded on large, low-copy number plasmids. These include genes conferring resistance to antibiotic and heavy metal toxicity, as well as genes involved in host cell invasion and pathogenicity. These large plasmids face a difficult challenge. To reduce the metabolic load they impose on the host cell, their copy numbers must be kept to a minimum (one to two per chromosome equivalent) (1). At such low-copy numbers, they can no longer rely on chance for their maintenance in the bacterial population. To be stably maintained, these low-copy number plasmids must, like chromosomes, be actively segregated to daughter cells before division. Two classes of plasmid segregation systems (Types I and II) have been known and studied for years (2), and recent work has uncovered several more (3, 4). Each system appears to be encoded on a single operon and to be composed of three pieces: 1) a centromeric DNA sequence, 2) a DNA-binding protein, and 3) a polymer-forming protein. The most well understood of these systems is the Type II segregation machinery encoded by the R1 drug-resistance plasmid. Segregation of R1 is driven by the par operon, which consists of a 150-bp centromeric sequence (parC), a repressor protein (ParR) that binds to the centromeric sequence, and a divergent actin-like protein (ParM) that polymerizes into dynamically unstable filaments in the presence of ATP (5). Binding of the ParR/parC complex to ParM filaments stabilizes them against catastrophic disassembly and promotes their elongation via insertional polymerization at the interface with the ParR/parC complex. When both ends of a ParM filament are bound to ParR/parC complexes, elongation of the filament pushes the attached plasmids in opposite directions.High-resolution structures of components of the R1 spindle are available (6, 7), but provide little information about the ultrastructure of the R1 spindle itself. The atomic structure of ParM monomers reveals a basic similarity to convention...

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Section: Discussionmentioning

confidence: 99%

“…Preparation of Gold Colloid-Samples of 5-and 10-nm gold colloid were prepared according to a literature procedure (13), described in detail by Claridge et al (14). The gold particles were used as an electron-dense tag for parC strands.…”

Section: Methodsmentioning

confidence: 99%

Protein-Nanocrystal Conjugates Support a Single Filament Polymerization Model in R1 Plasmid Segregation

Choi

Claridge

Garner

et al. 2008

Journal of Biological Chemistry

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“…Using DNA-AuNPs of fixed valences, we demonstrated that well-defined molecule-like nanoassemblies of heterogeneous oligomers can be readily formed. 4,41 It is also envisioned that these DNA-AuNPs can be further exploited to assemble high-ordered structures, for example, hydrogel or crystals with better control and homogeneity. [14][15][16] In addition, because we have obtained high yields of well-defined and uniform Au nanostructures, we expect that this system holds great promise for DNAregulated plasmonic applications 42,43 and biomolecular imaging.…”

Section: Discussionmentioning

confidence: 99%

Clicking DNA to gold nanoparticles: poly-adenine-mediated formation of monovalent DNA-gold nanoparticle conjugates with nearly quantitative yield

et al. 2015

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Monovalent DNA-gold nanoparticle (mDNA-AuNP) conjugates hold great promise for widespread applications, especially the construction of well-defined, molecule-like nanosystems. Previously reported methods all rely on the use of thiolated DNA to functionalize AuNPs, resulting in relatively low yields. Here, we report a facile method to rapidly prepare mDNA-AuNPs using a poly-adenine (polyA)-mediated approach. As polyA can selectively bind to AuNPs with high controllability of the surface density of DNA, we can use a DNA strand with a sufficiently long polyA to wrap around the surface of an individual AuNP, preventing further the adsorption of additional strands. Based on this observation, we obtained mDNA-AuNPs with a nearly quantitative yield of~90% using 80 As, as confirmed by both gel electrophoresis and transmission electron microscope observation. The yields of mDNA-AuNPs were insensitive to the stoichiometric ratio between DNA and AuNPs, suggesting the click chemistry-like nature of this polyA-mediated reaction. mDNA-AuNPs exhibited rapid kinetics and high efficiency for sequence-specific hybridization. More importantly, we demonstrated that AuNPs of fixed valences could form well-defined heterogenous oligomeric nanostructures with precise, atom-like control.

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“…Researchers in the Alivisatos group began the work in the area of discrete nanocrystal/biomolecule nanostructures. Since 1996, when the first paper was published on these structures [7], the area has flourished and has now grown to include many topics, from continuing work in synthesis of gold nanocrystal/DNA nanostructures [8] to use of semiconductor nanocrystals in cancer cell motility assays [9].…”

Section: Research In the Alivisatos Groupmentioning

confidence: 99%

Biomolecular Assembly of Gold Nanocrystals

Micheel

2005

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Directed Assembly of Discrete Gold Nanoparticle Groupings Using Branched DNA Scaffolds

Cited by 144 publications

References 40 publications

Protein-Nanocrystal Conjugates Support a Single Filament Polymerization Model in R1 Plasmid Segregation

Protein-Nanocrystal Conjugates Support a Single Filament Polymerization Model in R1 Plasmid Segregation

Clicking DNA to gold nanoparticles: poly-adenine-mediated formation of monovalent DNA-gold nanoparticle conjugates with nearly quantitative yield

Biomolecular Assembly of Gold Nanocrystals

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