TY - JOUR
T1 - Interdomain mobility and conformational stability of type III fibronectin domain pairs control surface adsorption, desorption and unfolding
AU - Pereira, P.
AU - Kelly, S.M.
AU - Gellert, P.R.
AU - van der Walle, Christopher F.
PY - 2008/6
Y1 - 2008/6
N2 - The 9th-10th type III fibronectin domain pair (9-10FNIII) has found widespread use as a biomimetic surface for cell adhesion. However, the effect of mutations to 9-10FNIII on its surface adsorption characteristics have not been investigated. Here we address this issue using total internal reflection fluorescence (TIRF) and circular dichroism spectroscopy, comparing two conformationally stable 9-10FNIII mutants against the wild type. Desorption of the 9-10FNIII mutants from the silica surface was minimal in comparison to desorption of 9-10FNIII. The extent and rate of protein desorption from silica was empirically matched by loss of secondary structure upon adsorption, with only the spectrum for 9-10FNIII showing extensive loss of the β-sandwich fold. For the proteins adsorbed to hydrophobic surfaces, only the CD spectra for the 9-10FNIII mutant constrained via an interdomain disulphide bridge showed similarity with the corresponding solution structure. Since the binding of 9-10FNIII to integrin α5β1 is highly dependent on the relative spatial arrangement of the two domains, we suggest that the observed differences in cell adhesion and spreading on wild type 9-10FNIII and mutants may in part be attributed to the extent of protein desorption and unfolding at the surface.
AB - The 9th-10th type III fibronectin domain pair (9-10FNIII) has found widespread use as a biomimetic surface for cell adhesion. However, the effect of mutations to 9-10FNIII on its surface adsorption characteristics have not been investigated. Here we address this issue using total internal reflection fluorescence (TIRF) and circular dichroism spectroscopy, comparing two conformationally stable 9-10FNIII mutants against the wild type. Desorption of the 9-10FNIII mutants from the silica surface was minimal in comparison to desorption of 9-10FNIII. The extent and rate of protein desorption from silica was empirically matched by loss of secondary structure upon adsorption, with only the spectrum for 9-10FNIII showing extensive loss of the β-sandwich fold. For the proteins adsorbed to hydrophobic surfaces, only the CD spectra for the 9-10FNIII mutant constrained via an interdomain disulphide bridge showed similarity with the corresponding solution structure. Since the binding of 9-10FNIII to integrin α5β1 is highly dependent on the relative spatial arrangement of the two domains, we suggest that the observed differences in cell adhesion and spreading on wild type 9-10FNIII and mutants may in part be attributed to the extent of protein desorption and unfolding at the surface.
KW - type III fibronectin domains
KW - surface adsorption
KW - circular dichroism
KW - total internal reflection fluorescence spectroscopy
UR - http://dx.doi.org/10.1016/j.colsurfb.2007.12.015
U2 - 10.1016/j.colsurfb.2007.12.015
DO - 10.1016/j.colsurfb.2007.12.015
M3 - Article
VL - 64
SP - 1
EP - 9
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
SN - 0927-7765
IS - 1
ER -