Packing of DNA

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Packing of DNA
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Nucleosomes
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The major structures in DNA compaction
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Human chromosomes during metaphase
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Replication
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Polymerase Chain Reaction
Taq Polymerase
1993 Nobel Prize in Chemistry Kary B. Mullis
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Polymerase Chain Reaction
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Sticky Ends Ligation
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Crossed Structures
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Complex Organizations
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Truncated Octahedron of DNA
A truncated octahedron contains six squares and
eight hexagons. Each edge of the truncated
octahedron contains two double helical turns of
DNA. The molecule contains 14 cyclic strands of
DNA. Each face of the octahedron corresponds to a
different cyclic strand.
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Seemans design of rigid DNA structures
Double crossover motif
Bulged junction triangle
Double crossover triangle
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Double crossover triangle
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2D Arrays of DX triangles of DNA
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Why Gold?
RS(cov) RAu(cov) 1.05 1.36 2.41 Å
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How to assemble nanoparticles into
superstructures?
Attach organic molecules capable of non-covalent
interactions. Ideally, those which are strong
and highly directional. First attempt
Hydrogen bonding
Au NPs covalently functionalized by DNA strands
were successfully synthesized by Mirkin et al.
in 1996. DNA hybridization-driven aggregation
of particles and changes in color were
observed. Drawback 1 Aggregation is random
and does not produce assemblies which are
well-defined in size or shape. Drawback 2
Aggregates have NO solution stability. They
precipitate as soon as they are formed.
A DNA-based method for rationally assembling
nanoparticles into macroscopic materials Mirkin
et al. Nature 1996. ISI citations 1680.
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Sensing
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Functional Applications
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Inorganic structures grown on DNA template