Abstract
Cell-matrix adhesions in migrating cells are usually mediated by integrins, α-β heterodimeric transmembrane proteins that link extracellular matrix molecules such as fibronectin to the cytoskeleton. We have synthesized the cytoplasmic domain of the β1-integrin (residues H738-K778) with a histidine tag at its N-terminus. The binding of this peptide to a lipid monolayer containing a chelated-nickel group (dimyristoylphosphatidyl choline-suberimide-nitriloacetic acid:nickel salt) mimics the native environment at the cytoplasmic leaflet of the plasma membrane. A Nanogold particle was covalently linked to cysteines introduced at the C-terminus and after residue T757 on the integrin peptide, and co-crystallized with chicken smooth muscle α-actinin. The 2-D arrays of the β1-integrin-α-actinin complex were examined by cryoelectron microscopy, with and without the gold label. Averaged projections were calculated for each specimen along with a difference map to determine the relative position of the gold-labeled β1-integrin peptide. The difference maps indicate that the β1-integrin cytoplasmic domain binds α-actinin between the first and second, 3-helix motifs in the central rod domain.
Original language | English (US) |
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Pages (from-to) | 290-302 |
Number of pages | 13 |
Journal | Journal of Structural Biology |
Volume | 149 |
Issue number | 3 |
DOIs | |
State | Published - Mar 2005 |
All Science Journal Classification (ASJC) codes
- Structural Biology