Biomedical Engineering Reference
In-Depth Information
pIII
pVI
pVII
pVIII
pIX
DNA
Figure 7.5
(See companion CD for color igure.)
.Schematic.of.the.M13.bacteriophage.structure.
hairpin.loop.region.that.recruits.dimers.of.the.viral.packaging.protein.pV,.which.is.later.
replaced.by.pVIII.during.extrusion.(Russel.and.Model.1989)..The.major.coat.protein.pVIII.
is. arranged. helically. along. the. length. of. the. capsid. and. has. a. slight. outward. pitch.. The.
inward-facing. base. of. pVIII. contains. positively. charged. amino. acid. residues,. capable. of.
interacting. with. DNA. on. the. capsid. interior.. After. the. entire. genome. has. been. encap-
sidated. by. pVIII,. the. capping. proteins. pIII. and. pVI. are. added. to. the. structure. resulting.
in. release. of. the. virion. from. the. host.. The. self-assembly. mechanism. of. M13. is. common.
among.ilamentous.phages,.but.unique.in.comparison.with.other.virus.systems.(Rakonjac.
et.al..2011).
7.3.2 Material Templating
As.mentioned.previously,.research.into.screening.peptides.capable.of.binding.inorganic.
surfaces.has.been.under.investigation.for.quite.some.time..With.respect.to.viral.nano-
bioengineering,.the.development.of.phage.display.technology.has.allowed.a.unique.role.
for.M13.when.compared.to.other.virus.systems.discussed.in.this.chapter..Phage.display.
enables.researchers.to.select.for.peptides.capable.of.binding.or.nucleating.inorganic.sub-
stances..Peptides.to.be.screened.can.be.inserted.either.into.the.major.coat.protein.pVIII,.
and.thus.thousands.of.copies.will.be.expressed.along.the.entire.capsid.length,.or.into.
the.capsid.end.proteins.pIII,.pVII,.and.pIX,.expressing.just.a.few.copies.and.at.only.one.
end.of.the.phage.(Smith.and.Petrenko.1997)..Upon.successful.screening.and.selection.of.
peptides.with.desired.afinities,.the.advantages.of.having.the.peptides.aligned.in.a.one-
dimensional.arrangement.along.the.M13.backbone.are.plentiful..Bottom-up.nanoscale.
fabrication.is.inherently.dificult.based.only.on.the.requirement.for.precise.placement.
of. building. blocks. or. materials. precursors. on. the. nanoscale.. The. one-dimensional.
