We recently developed a binding assay format by incorporating native transmembrane receptors into artificialp
hosp
holipid bilayers on biosensor devices for surfaceplasmon resonance spectroscopy. By extending t
he met
hodto surface plasmon-en
hanced fluorescence spectroscopy(SPFS), sensitive recording of t
he association of even verysmall ligands is enabled. Herewit
h, we monitored bindingof synt
hetic mono- and oligomeric RGD-based peptidesand peptidomimetics to integrins
![](/images/gifc<font color=)
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![](/images/gifc<font color=)
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![](/images/gifc<font color=)
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![](/images/gifc<font color=)
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having confirmed correct orientation and functionality ofmembrane-embedded integrins. We evaluated integrinbinding of RGD multimers linked toget
her via amino
hexanoic acid (A
hx) spacers and s
howed t
hat t
he dimerrevealed
hig
her binding activity t
han t
he tetramer, followed by t
he RGD monomers. T
he peptidomimetic wasalso found to be
hig
hly active wit
h a slig
htly
hig
herselectivity toward
![](/images/gifc<font color=)
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![](/images/gifc<font color=)
hars/beta2.gif" BORDER=0 ALIGN="middle">3. T
he different compounds werealso evaluated in in vitro cell ad
hesion tests for t
heircapacity to interfere wit
h ![](/images/gifc<font color=)
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![](/images/gifc<font color=)
hars/beta2.gif" BORDER=0 ALIGN="middle">3-mediated cell attac
hmentto vitronectin. We
hereby demonstrated t
hat t
he differentRGD monomers were similarly effective; t
he RGD dimerand tetramer s
howed comparable IC
50 values, w
hic
h were,
however, significantly
hig
her t
han t
hose of t
he monomers.Best cell detac
hment from vitronectin was ac
hieved by t
hepeptidomimetic. T
he novel SPFS-binding assay platformproves to be a suitable, reliable, and sensitive met
hod tomonitor t
he binding capacity of small ligands to nativetransmembrane receptors,
here demonstrated for integrins.