Biomedical Engineering Reference
In-Depth Information
5
From RNA
Structures to RNA Nanomachines
Sabarinath Jayaseelan, Paul D. Kutscha, Francis Doyle, and Scott A. Tenenbaum
CONTENTS
5.1. Introduction......................................................................................................................... 113
5.2. Structural.Order.of.RNA................................................................................................... 114
5.3. RNA:.A.Paradigm.Shift.from.Messenger.to.Protagonist............................................. 117
5.3.1. RNA:.A.Natural.Nanomachine............................................................................ 117
5.3.2. Noncoding.RNA.Regulation................................................................................ 119
5.4. RNA.Nanotechnology....................................................................................................... 120
5.5. Conclusions.and.Perspectives.......................................................................................... 123
References..................................................................................................................................... 123
5.1 Introduction
Deoxyribonucleic.acid.(DNA).and.ribonucleic.acid.(RNA).are.the.primary.means.of.data.
storage.and.transportation.within.the.cell..Both.are.polymer.chains.made.up.of.a.sugar.
phosphate. backbone. connected. to. one. of. four. bases:. adenine. (A),. guanine. (G),. cytosine.
(C),.and.thymine.(T).(or.uracil.[U].in.the.case.of.RNA)..DNA.is.the.primary.medium.of.
long-term. information. storage. in. the. cell.. Each. molecule. of. DNA. is. made. up. of. a. long.
chain.of.nucleotides,.typically.millions.of.base.pairs,.and.exhibits.canonical.base.pairing.
of. A-T. and. G-C. between. two. nucleotide. chains.. These. base. pairs. are. brought. about. by.
hydrogen.bonding.between.matching.bases,.creating.a.stable.bond.and.very.speciic.base.
positioning..This.complementary.base-pairing.forces.the.DNA.molecule.to.adopt.double.
helix. geometry. (Watson. and. Crick. 1953;. Wang. et. al.. 1979;. Basham. et. al.. 1995).. Within.
the.cell,.the.strong.complementary.base.pairing.causes.DNA.to.adopt.one.of.three.helix.
conformations,.giving.great.conformational.stability.but.limiting.the.other.possible.inter-
actions..Genomic.DNA.is.concentrated.within.the.nucleus.of.the.cell.and.is.typically.in.
a.complex.with.packing.proteins.called.histones.to.remain.compact..DNA.is.also.chemi-
cally.protected.by.residing.within.the.nucleus.and.is.shielded.from.enzymatic.degrada-
tion.or.major.changes.in.sequence..Additionally,.DNA.inserted.into.a.cell.will.be.largely.
left.alone.until.incorporation,.making.DNA.insertion.into.cells.relatively.easier..All.these.
advantages. advanced. the. DNA-based. nanotechnology. ield. forward. while. RNA-based.
nanotechnology.has.lagged.behind.
RNA.was.originally.assumed.to.act.solely.as.a.transition.molecule.as.DNA.is.converted.
into. protein,. shuttling. from. the. nucleus. to. the. cytoplasm. where. it. serves. as. a. template.
for.protein.translation..RNA.is.chemically.similar.to.DNA.and.exhibits.certain.amount.
of.complementarity..Strands.of.RNA.are.typically.far.shorter.(hundreds.or.thousands.of.
113
