Skip to main content

Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy.

Publication ,  Journal Article
Carrell, NA; Fitzgerald, LA; Steiner, B; Erickson, HP; Phillips, DR
Published in: J Biol Chem
February 10, 1985

The glycoprotein (GP) IIb-IIIa complex was isolated from human platelet membranes and examined for glycoprotein stoichiometry and morphology. To determine the ratio of glycoproteins in the complex, the isolated glycoproteins were solubilized with sodium dodecyl sulfate and separated by high-performance liquid chromatography. Quantitative amino acid analysis of individual glycoproteins showed that the ratio of GP IIb to GP IIIa in the Ca2+-dependent complex was 0.93:1. Morphology was determined by electron microscopy of rotary-shadowed and negatively stained specimens. Individual complexes consisted of two domains: an oblong head of approximately 8 X 10 nm with two rodlike tails extending approximately 14-17 nm from one side of the head. Treatment of the isolated complex with EDTA resulted in the appearance of a mixture of oblong and filamentous structures, which could be separated by a sucrose gradient sedimentation in Triton X-100. As seen by rotary and unidirectional shadowing, GP IIb was a compact structure, approximately 8 X 10 nm in size. Isolated GP IIIa was more heterogeneous but was most often observed in an elongated form, varying in length from 20 to 30 nm and in width from 2 to 3 nm. By comparing these structures to that of the heterodimer complex, it was determined that the oblong domain was GP IIb and the rodlike tails were GP IIIa. Each milligram of isolated GP IIb-IIIa complex bound 0.30 mg of [3H]Triton X-100, indicating that the glycoprotein complex contained limited hydrophobic domains. Upon removal of detergent, GP IIb-IIIa complexes formed aggregates that sedimented in sucrose gradients as a diffuse peak ranging from 14 to 32 s. Examination of these aggregates by electron microscopy showed that they were composed of clusters or "rosettes" of 2 to 20 or more of the GP IIb-IIIa complexes. The orientation of these rosettes was such that the tails were joined in the center, with the head portions directed away from the interacting tails. It thus appears that the primary hydrophobic domains of the GP IIb-IIIa complex exist at the tips of the GP IIIa tails. Because the GP IIb-IIIa complex is an intrinsic membrane glycoprotein, these findings indicate a potential membrane attachment site for the GP IIb-IIIa complexes.

Duke Scholars

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

February 10, 1985

Volume

260

Issue

3

Start / End Page

1743 / 1749

Location

United States

Related Subject Headings

  • Polyethylene Glycols
  • Platelet Membrane Glycoproteins
  • Octoxynol
  • Microscopy, Electron
  • Membrane Proteins
  • Macromolecular Substances
  • Humans
  • Glycoproteins
  • Edetic Acid
  • Chromatography, High Pressure Liquid
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Carrell, N. A., Fitzgerald, L. A., Steiner, B., Erickson, H. P., & Phillips, D. R. (1985). Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy. J Biol Chem, 260(3), 1743–1749.
Carrell, N. A., L. A. Fitzgerald, B. Steiner, H. P. Erickson, and D. R. Phillips. “Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy.J Biol Chem 260, no. 3 (February 10, 1985): 1743–49.
Carrell NA, Fitzgerald LA, Steiner B, Erickson HP, Phillips DR. Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy. J Biol Chem. 1985 Feb 10;260(3):1743–9.
Carrell, N. A., et al. “Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy.J Biol Chem, vol. 260, no. 3, Feb. 1985, pp. 1743–49.
Carrell NA, Fitzgerald LA, Steiner B, Erickson HP, Phillips DR. Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy. J Biol Chem. 1985 Feb 10;260(3):1743–1749.

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

February 10, 1985

Volume

260

Issue

3

Start / End Page

1743 / 1749

Location

United States

Related Subject Headings

  • Polyethylene Glycols
  • Platelet Membrane Glycoproteins
  • Octoxynol
  • Microscopy, Electron
  • Membrane Proteins
  • Macromolecular Substances
  • Humans
  • Glycoproteins
  • Edetic Acid
  • Chromatography, High Pressure Liquid