Electron microscopy and structural model of human fibronectin receptor. |
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| Authors: | M V Nermut N M Green P Eason S S Yamada and K M Yamada |
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| Affiliation: | National Institute for Medical Research, The Ridgeway, London, UK. |
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| Abstract: | Highly-purified human fibronectin receptor (a heterodimer of two distinct subunits, alpha and beta) was studied using electron microscopy and a variety of preparative procedures. It was found that the receptor consists of a globular head approximately 80 by 120 A and two tails about 20 A thick and 180-200 A long. The whole complex is approximately 280 A long. At low concentrations of detergent the receptor forms doublets, triplets or rosettes associated with the tails which possess the transmembrane portion of the molecule. Computer-assisted structure prediction using the published amino acid sequence of both subunits showed differences in the secondary structure of the tails, the alpha-tail being rich in beta-strands, the beta-tail having five cysteine-rich repeats analogous to the EGF-like repeats of laminin. Estimates of the length of the tails from the predicted structure conformed well with the dimensions obtained from electron micrographs. |
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