Jump to main content
Jump to site search

Issue 1, 2012
Previous Article Next Article

Bimolecular integrin–ligand interactions quantified using peptide-functionalized dextran-coated microparticles

Author affiliations

Abstract

Integrins play a key role in cell–cell and cell–matrix interactions. Artificial surfaces grafted with integrin ligands, mimicking natural interfaces, have been used to study integrin-mediated cell adhesion. Here we report the use of a new chemical engineering technology in combination with single-molecule nanomechanical measurements to quantify peptide binding to integrins. We prepared latex beads with covalently-attached dextran. The beads were then functionalized with the bioactive peptides, cyclic RGDFK (cRGD) and the fibrinogen γC-dodecapeptide (H12), corresponding to the active sites for fibrinogen binding to the platelet integrin αIIbβ3. Using optical tweezers-based force spectroscopy to measure non-specific proteinprotein interactions, we found the dextran-coated beads nonreactive towards fibrinogen, thus providing an inert platform for biospecific modifications. Using periodate oxidation followed by reductive amination, we functionalized the bead-attached dextran with either cRGD or H12 and used the peptide-grafted beads to measure single-molecule interactions with the purified αIIbβ3. Bimolecular force spectroscopy revealed that the peptide-functionalized beads were highly and specifically reactive with the immobilized αIIbβ3. Further, the cRGD- and H12-functionalized beads displayed a remarkable interaction profile with a bimodal force distribution up to 90 pN. The cRGD–αIIbβ3 interactions had greater binding strength than that of H12–αIIbβ3, indicating that they are more stable and resistant mechanically, consistent with the platelet reactivity of RGD-containing ligands. Thus, the results reported here describe the mechanistic characteristics of αIIbβ3–ligand interactions, confirming the utility of peptide-functionalized latex beads for the quantitative analysis of molecular recognition.

Graphical abstract: Bimolecular integrin–ligand interactions quantified using peptide-functionalized dextran-coated microparticles

Back to tab navigation

Publication details

The article was received on 14 Aug 2011, accepted on 26 Oct 2011 and first published on 28 Nov 2011


Article type: Paper
DOI: 10.1039/C1IB00085C
Citation: Integr. Biol., 2012,4, 84-92
  •   Request permissions

    Bimolecular integrin–ligand interactions quantified using peptide-functionalized dextran-coated microparticles

    J. E. P. Sun, J. Vranic, R. J. Composto, C. Streu, P. C. Billings, J. S. Bennett, J. W. Weisel and R. I. Litvinov, Integr. Biol., 2012, 4, 84
    DOI: 10.1039/C1IB00085C

Search articles by author

Spotlight

Advertisements