Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Integr Biol (Camb). 2012 Jan;4(1):84-92. doi: 10.1039/c1ib00085c. Epub 2011 Nov 28.

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

Author information

  • 1Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

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 protein-protein 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.

This journal is © The Royal Society of Chemistry 2012

PMID:
22120019
[PubMed - indexed for MEDLINE]
PMCID:
PMC3337774
Free PMC Article

Images from this publication.See all images (8)Free text

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Royal Society of Chemistry Icon for PubMed Central
    Loading ...
    Write to the Help Desk