Skip to main content
NCBI home page
Protein Science : A Publication of the Protein Society logoLink to Protein Science : A Publication of the Protein Society
. 1993 Dec;2(12):2154–2166. doi: 10.1002/pro.5560021215

Modeling the alpha IIb beta 3 integrin solution conformation.

M Rocco 1, B Spotorno 1, R R Hantgan 1
PMCID: PMC2142313  PMID: 7507753

Abstract

The alpha IIb beta 3 platelet integrin is the prototypical member of a widely distributed class of transmembrane receptors formed by the noncovalent association of alpha and beta subunits. Electron microscopic (EM) images of the alpha IIb beta 3 complex show an asymmetric particle with a globular domain from which two extended regions protrude to contact the lipid bilayer. Distance constraints provided by disulfide bond patterns, epitope mapping, and ligand mimetic cross-linking studies rather suggest a somewhat more compact conformation for the alpha IIb beta 3 complex. We have studied the shape of detergent-solubilized alpha IIb beta 3 by employing a low-resolution modeling procedure in which each polypeptide has been represented as an array of interconnected, nonoverlapping spheres (beads) of various sizes. The number, size, and three-dimensional relationships among the beads were defined either solely by dimensions obtained from published EM images of integrin receptors (EM models, 21 beads), or solely by interdomain constraints derived from published biochemical data (biochemical model, 37 beads). Interestingly, although no EM data were employed in its construction, the resulting overall shape of the biochemical model was still compatible with the EM data. Both kinds of models were then evaluated for their calculated solution properties. The more elongated EM models have diffusion and sedimentation coefficients that differ, at best, by +2% and -18% from the experimental values, determined, respectively, in octyl glucoside and Triton X-100. On the other hand, the parameters calculated for the more compact biochemical model showed a more consistent agreement with experimental values, differing by -7% (octyl glucoside) to -6% (Triton X-100). Thus, it appears that using the biochemical constraints as a starting point has resulted in not only a more detailed model of the detergent-solubilized alpha IIb beta 3 complex, where the relative spatial location of specific domains the size of 5-10 kDa can be tentatively mapped, but in a model that can also reconcile the electron microscopy with the biochemical and the solution data.

Full Text

The Full Text of this article is available as a PDF (2.2 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Albelda S. M., Buck C. A. Integrins and other cell adhesion molecules. FASEB J. 1990 Aug;4(11):2868–2880. [PubMed] [Google Scholar]
  2. Allen J. P., Feher G., Yeates T. O., Komiya H., Rees D. C. Structure of the reaction center from Rhodobacter sphaeroides R-26: the protein subunits. Proc Natl Acad Sci U S A. 1987 Sep;84(17):6162–6166. doi: 10.1073/pnas.84.17.6162. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Calvete J. J., Alvarez M. V., Rivas G., Hew C. L., Henschen A., González-Rodríguez J. Interchain and intrachain disulphide bonds in human platelet glycoprotein IIb. Localization of the epitopes for several monoclonal antibodies. Biochem J. 1989 Jul 15;261(2):551–560. doi: 10.1042/bj2610551. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Calvete J. J., Arias J., Alvarez M. V., Lopez M. M., Henschen A., Gonzalez-Rodriguez J. Further studies on the topography of human platelet glycoprotein IIb. Localization of monoclonal antibody epitopes and the putative glycoprotein IIa- and fibrinogen-binding regions. Biochem J. 1991 Feb 1;273(Pt 3):767–775. doi: 10.1042/bj2730767. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Calvete J. J., Arias J., Alvarez M. V., Lopez M. M., Henschen A., González-Rodríguez J. Further studies on the topography of the N-terminal region of human platelet glycoprotein IIIa. Localization of monoclonal antibody epitopes and the putative fibrinogen-binding sites. Biochem J. 1991 Mar 1;274(Pt 2):457–463. doi: 10.1042/bj2740457. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Calvete J. J., Henschen A., González-Rodríguez J. Complete localization of the intrachain disulphide bonds and the N-glycosylation points in the alpha-subunit of human platelet glycoprotein IIb. Biochem J. 1989 Jul 15;261(2):561–568. doi: 10.1042/bj2610561. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Calvete J. J., Schäfer W., Mann K., Henschen A., González-Rodríguez J. Localization of the cross-linking sites of RGD and KQAGDV peptides to the isolated fibrinogen receptor, the human platelet integrin glycoprotein IIb/IIIa. Influence of peptide length. Eur J Biochem. 1992 Jun 15;206(3):759–765. doi: 10.1111/j.1432-1033.1992.tb16982.x. [DOI] [PubMed] [Google Scholar]
  8. Carrell N. A., Fitzgerald L. A., Steiner B., Erickson H. P., Phillips D. R. Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy. J Biol Chem. 1985 Feb 10;260(3):1743–1749. [PubMed] [Google Scholar]
  9. Charo I. F., Nannizzi L., Phillips D. R., Hsu M. A., Scarborough R. M. Inhibition of fibrinogen binding to GP IIb-IIIa by a GP IIIa peptide. J Biol Chem. 1991 Jan 25;266(3):1415–1421. [PubMed] [Google Scholar]
  10. D'Souza S. E., Ginsberg M. H., Burke T. A., Lam S. C., Plow E. F. Localization of an Arg-Gly-Asp recognition site within an integrin adhesion receptor. Science. 1988 Oct 7;242(4875):91–93. doi: 10.1126/science.3262922. [DOI] [PubMed] [Google Scholar]
  11. D'Souza S. E., Ginsberg M. H., Burke T. A., Plow E. F. The ligand binding site of the platelet integrin receptor GPIIb-IIIa is proximal to the second calcium binding domain of its alpha subunit. J Biol Chem. 1990 Feb 25;265(6):3440–3446. [PubMed] [Google Scholar]
  12. Eirín M. T., Calvete J. J., González-Rodríguez J. New isolation procedure and further biochemical characterization of glycoproteins IIb and IIIa from human platelet plasma membrane. Biochem J. 1986 Nov 15;240(1):147–153. doi: 10.1042/bj2400147. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Farrell D. H., Thiagarajan P., Chung D. W., Davie E. W. Role of fibrinogen alpha and gamma chain sites in platelet aggregation. Proc Natl Acad Sci U S A. 1992 Nov 15;89(22):10729–10732. doi: 10.1073/pnas.89.22.10729. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Garcia de la Torre J. G., Bloomfield V. A. Hydrodynamic properties of complex, rigid, biological macromolecules: theory and applications. Q Rev Biophys. 1981 Feb;14(1):81–139. doi: 10.1017/s0033583500002080. [DOI] [PubMed] [Google Scholar]
  15. Ginsberg M. H., Loftus J. C., Plow E. F. Cytoadhesins, integrins, and platelets. Thromb Haemost. 1988 Feb 25;59(1):1–6. [PubMed] [Google Scholar]
  16. Gregory L., Davis K. G., Sheth B., Boyd J., Jefferis R., Nave C., Burton D. R. The solution conformations of the subclasses of human IgG deduced from sedimentation and small angle X-ray scattering studies. Mol Immunol. 1987 Aug;24(8):821–829. doi: 10.1016/0161-5890(87)90184-2. [DOI] [PubMed] [Google Scholar]
  17. Hantgan R. R., Endenburg S. C., Cavero I., Marguerie G., Uzan A., Sixma J. J., de Groot P. G. Inhibition of platelet adhesion to fibrin(ogen) in flowing whole blood by Arg-Gly-Asp and fibrinogen gamma-chain carboxy terminal peptides. Thromb Haemost. 1992 Dec 7;68(6):694–700. [PubMed] [Google Scholar]
  18. Hantgan R. R. Localization of the domains of fibrin involved in binding to platelets. Biochim Biophys Acta. 1988 Jan 18;968(1):36–44. doi: 10.1016/0167-4889(88)90041-9. [DOI] [PubMed] [Google Scholar]
  19. Henderson R., Baldwin J. M., Ceska T. A., Zemlin F., Beckmann E., Downing K. H. Model for the structure of bacteriorhodopsin based on high-resolution electron cryo-microscopy. J Mol Biol. 1990 Jun 20;213(4):899–929. doi: 10.1016/S0022-2836(05)80271-2. [DOI] [PubMed] [Google Scholar]
  20. Jennings L. K., Phillips D. R. Purification of glycoproteins IIb and III from human platelet plasma membranes and characterization of a calcium-dependent glycoprotein IIb-III complex. J Biol Chem. 1982 Sep 10;257(17):10458–10466. [PubMed] [Google Scholar]
  21. Lewis J. C., Johnson C., Ramsamooj P., Hantgan R. R. Orientation and specificity of fibrin protofibril binding to ADP-stimulated platelets. Blood. 1988 Dec;72(6):1992–2000. [PubMed] [Google Scholar]
  22. Nermut M. V., Green N. M., Eason P., Yamada S. S., Yamada K. M. Electron microscopy and structural model of human fibronectin receptor. EMBO J. 1988 Dec 20;7(13):4093–4099. doi: 10.1002/j.1460-2075.1988.tb03303.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Parise L. V., Phillips D. R. Platelet membrane glycoprotein IIb-IIIa complex incorporated into phospholipid vesicles. Preparation and morphology. J Biol Chem. 1985 Feb 10;260(3):1750–1756. [PubMed] [Google Scholar]
  24. Perkins S. J., Nealis A. S., Sutton B. J., Feinstein A. Solution structure of human and mouse immunoglobulin M by synchrotron X-ray scattering and molecular graphics modelling. A possible mechanism for complement activation. J Mol Biol. 1991 Oct 20;221(4):1345–1366. doi: 10.1016/0022-2836(91)90937-2. [DOI] [PubMed] [Google Scholar]
  25. Ramsamooj P., Doellgast G. J., Hantgan R. R. Inhibition of fibrin(ogen) binding to stimulated platelets by a monoclonal antibody specific for a conformational determinant of GPIIIa. Thromb Res. 1990 Jun 15;58(6):577–592. doi: 10.1016/0049-3848(90)90304-u. [DOI] [PubMed] [Google Scholar]
  26. Ramsamooj P., Lively M. O., Hantgan R. R. Evidence that the central region of glycoprotein IIIa participates in integrin receptor function. Biochem J. 1991 Jun 15;276(Pt 3):725–732. doi: 10.1042/bj2760725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Rao S. P., Poojary M. D., Elliott B. W., Jr, Melanson L. A., Oriel B., Cohen C. Fibrinogen structure in projection at 18 A resolution. Electron density by co-ordinated cryo-electron microscopy and X-ray crystallography. J Mol Biol. 1991 Nov 5;222(1):89–98. doi: 10.1016/0022-2836(91)90739-s. [DOI] [PubMed] [Google Scholar]
  28. Rivas G. A., Aznárez J. A., Usobiaga P., Saiz J. L., González-Rodríguez J. Molecular characterization of the human platelet integrin GPIIb/IIIa and its constituent glycoproteins. Eur Biophys J. 1991;19(6):335–345. doi: 10.1007/BF00183324. [DOI] [PubMed] [Google Scholar]
  29. Rocco M., Carson M., Hantgan R., McDonagh J., Hermans J. Dependence of the shape of the plasma fibronectin molecule on solvent composition. Ionic strength and glycerol content. J Biol Chem. 1983 Dec 10;258(23):14545–14549. [PubMed] [Google Scholar]
  30. Rocco M., Infusini E., Daga M. G., Gogioso L., Cuniberti C. Models of fibronectin. EMBO J. 1987 Aug;6(8):2343–2349. doi: 10.1002/j.1460-2075.1987.tb02510.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Roth M., Arnoux B., Ducruix A., Reiss-Husson F. Structure of the detergent phase and protein-detergent interactions in crystals of the wild-type (strain Y) Rhodobacter sphaeroides photochemical reaction center. Biochemistry. 1991 Oct 1;30(39):9403–9413. doi: 10.1021/bi00103a003. [DOI] [PubMed] [Google Scholar]
  32. Ruoslahti E., Pierschbacher M. D. New perspectives in cell adhesion: RGD and integrins. Science. 1987 Oct 23;238(4826):491–497. doi: 10.1126/science.2821619. [DOI] [PubMed] [Google Scholar]
  33. Smith J. W., Cheresh D. A. Integrin (alpha v beta 3)-ligand interaction. Identification of a heterodimeric RGD binding site on the vitronectin receptor. J Biol Chem. 1990 Feb 5;265(4):2168–2172. [PubMed] [Google Scholar]
  34. Tanford C., Nozaki Y., Reynolds J. A., Makino S. Molecular characterization of proteins in detergent solutions. Biochemistry. 1974 May 21;13(11):2369–2376. doi: 10.1021/bi00708a021. [DOI] [PubMed] [Google Scholar]
  35. Venable R. M., Pastor R. W. Frictional models for stochastic simulations of proteins. Biopolymers. 1988 Jun;27(6):1001–1014. doi: 10.1002/bip.360270609. [DOI] [PubMed] [Google Scholar]
  36. Weisel J. W., Nagaswami C., Vilaire G., Bennett J. S. Examination of the platelet membrane glycoprotein IIb-IIIa complex and its interaction with fibrinogen and other ligands by electron microscopy. J Biol Chem. 1992 Aug 15;267(23):16637–16643. [PubMed] [Google Scholar]
  37. de Vos A. M., Ultsch M., Kossiakoff A. A. Human growth hormone and extracellular domain of its receptor: crystal structure of the complex. Science. 1992 Jan 17;255(5042):306–312. doi: 10.1126/science.1549776. [DOI] [PubMed] [Google Scholar]

Articles from Protein Science : A Publication of the Protein Society are provided here courtesy of The Protein Society

RESOURCES