Chemistry Reference
In-Depth Information
cold-resistant. organisms. [4].. In. general,. understanding. the. factors. that. lead. to. the.
conformational.stability.of.a.carbohydrate.is.extremely.challenging.due.to.the.many.
torsional.degrees.of.freedom.present.in.these.molecules.[5-7].
Mannopyranoside. is. important. in. bacterial. pathogenesis. since. it. is. among. the.
most.common.biomolecules.in.the.lectins.of.enterobacteria.that.regulates.the.adher-
ence.of.the.bacteria.to.host.epithelial.cells.[8]..Furthermore,.high.mannopyranoside.
precursors.are.found.on.the.glycosylation.sites.of.glycoproteins.[9]..The.structural.
and.conformational.changes.of.carbohydrates.(including.mannopyranosides),.which.
are.the.building.blocks.of.eukaryotic.cell.surfaces,.are.used.in.the.design.of.biomark-
ers. that. detect. structural. and. conformational. changes. associated. with. the. onset. of.
cancer.[8,10,17-20]..The.structural.change.of.mannopyranoside.complexes.is.there-
fore.a.code.for.cellular.physiology..An.understanding.of.this.code.at.both.molecular.
and. functional. levels. is. emerging.. Although. it. has. been. appreciated. that. carbohy-
drate. expression. changes. with. cellular. condition,. progress. toward. delineating. the.
molecular. basis. of. carbohydrate. function. has. been. slow. relative. to. the. studies. of.
proteins.and.nucleic.acids..This.slow.progress.is.partly.due.to.the.complex.structure.
and. high. lexibility. of. carbohydrates,. unlike. other. biomolecules. such. as. proteins..
Furthermore,.studies.on.the.mannopyranoside-type.carbohydrates.on.the.gp120.pro-
tein,.which.is.on.the.surface.of.HIV-1,.show.that.an.understanding.of.the.structure-
function.relationship.of.mannopyranoside-containing.glycan.complexes.is.essential.
for.designing.carbohydrate-based.HIV.vaccines.and.antiviral.agents.[19-23].
Not.only.the.carbohydrates.themselves.but.also.their.interactions.and.bindings.to.
metal.ions,.such.as.iron.ions,.are.crucial.in.biological.and.environmental.processes..For.
instance,.iron.nanoparticles.and.their.complexes.with.carbohydrates.have.been.used.
in. new. treatment. strategies. in. regenerative. medicine,. i.e.,. stem. cell. labeling. [11-14]..
Moreover,. iron. deiciency. causes. bacterial. pathogens,. which. involve. carbohydrates.
attached. to. the. cell. surface. (as. described. above),. to. produce. greater. tissue. damage.
because.many.virulence.factors.are.determined.by.the.iron.supply.[15-18]..In.environ-
mental.chemistry,.carbohydrates.and.iron.ion.interactions.play.unique.roles.in.diverse.
processes..For.example,.microbial.bacteria.are.known.to.scavenge.iron.particles.and.to.
induce.crystallization.of.unexpected.phases.called.nontronite,.which.is.an.iron-rich.clay.
mineral.[9]..There.are.hundreds.of.additional.processes.in.biology.and.environmental.
chemistry.beyond.the.several.examples.provided.here.in.which.carbohydrate.and.iron.
interactions.play.crucial.roles..In.general,.studies.of.structure-function.relationships.in.
biometallic.molecular.systems.are.of.critical.importance.in.basic.and.applied.sciences.
Both. experimental. and. theoretical. studies. of. the. structure. of. carbohydrate. and.
iron.complexes.pose.a.challenge.due.to.the.possibility.of.multi-dentate.coordination.
of.the.iron.ion.and.the.many.degrees.of.freedom.present.in.carbohydrates..In.addi-
tion,.the.fast.dynamics.associated.with.the.small.size.of.solvent.molecules.and.short.
timescales.further.challenge.the.carbohydrate.studies.in.aqueous.solution..Since.the.
experimental.studies.of.Saltman.in.the.early.1960s.on.carbohydrates.and.iron.com-
plexes.[24-26].and.the.studies.on.carbohydrate.chelating.ability.by.Davis.and.Deller.
[27],.there.has.been.a.large.gap.in.the.scientiic.literature.regarding.the.understand-
ing.of.these.biometallic.molecular.systems..A.recent.exception.is.the.studies.of.Rao.
et.al.,.who.proposed.synthetic.strategies.for.the.isolation,.characterization,.and.stabi-
lization.of.carbohydrate.and.iron.complexes.[28].
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