Folding of the N-terminal, ligand-binding region of integrin alpha-subunits into a beta-propeller domain

Proc Natl Acad Sci U S A. 1997 Jan 7;94(1):65-72. doi: 10.1073/pnas.94.1.65.

Abstract

The N-terminal approximately 440 aa of integrin alpha subunits contain seven sequence repeats. These are predicted here to fold into a beta-propeller domain. A homologous domain from the enzyme phosphatidylinositol phospholipase D is predicted to have the same fold. The domains contain seven four-stranded beta-sheets arranged in a torus around a pseudosymmetry axis. The trimeric G-protein beta subunit (G beta) appears to be the most closely related beta-propeller. Integrin ligands and a putative Mg2+ ion are predicted to bind to the upper face of the beta-propeller. This face binds substrates in beta-propeller enzymes and is used by the G protein beta subunit to bind the G protein alpha subunit. The integrin alpha subunit I domain, which is structurally homologous to the G protein alpha subunit, is tethered to the top of the beta-propeller domain by a hinge that may allow movement of the domains relative to one another. The Ca2+-binding motifs in integrin alpha subunits are on the lower face of the beta-propeller.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Binding Sites
  • Consensus Sequence
  • Disulfides
  • Forecasting
  • Integrins / chemistry*
  • Ligands
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation*
  • Protein Folding*
  • Protein Structure, Secondary
  • Repetitive Sequences, Nucleic Acid*
  • Sequence Alignment

Substances

  • Disulfides
  • Integrins
  • Ligands