Different cation binding to the I domains of alpha1 and alpha2 integrins: implication of the binding site structure

FEBS Lett. 1999 Sep 3;457(3):311-5. doi: 10.1016/s0014-5793(99)01063-7.


In the present work, we studied the interactions of recombinant alpha1 and alpha2 integrin I domains with cations Tb(3+), Mn(2+), Mg(2+) and Ca(2+). We observed that alpha1 and alpha2 I domains bind these cations with significantly different characteristics. The binding of Mg(2+) by the alpha1 I domain was accompanied by significant changes of tryptophan fluorescence which could be interpreted as a conformational change. Comparison of the alpha1 integrin I domain structure obtained by comparative modeling with a known structure of the alpha2 integrin I domain shows distinct differences in the metal ion binding sites which could explain the differences in cation binding.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, CD / chemistry*
  • Antigens, CD / metabolism*
  • Binding Sites
  • Cations / metabolism*
  • Fluorescence
  • Integrin alpha1
  • Integrin alpha2
  • Magnesium / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Terbium / metabolism
  • Tryptophan / chemistry


  • Antigens, CD
  • Cations
  • Integrin alpha1
  • Integrin alpha2
  • Recombinant Proteins
  • Terbium
  • Tryptophan
  • Magnesium