Electron microscopy and structural model of human fibronectin receptor.
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.
Nermut
M V
MV
National Institute for Medical Research, The Ridgeway, London, UK.
Green
N M
NM
Eason
P
P
Yamada
S S
SS
Yamada
K M
KM
D000595:Amino Acid Sequence; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011487:Protein Conformation; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic
D005353:Fibronectins; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic