Characterization of the Heparin Binding Properties of Annexin II Tetramer
In this report, we have characterized the interaction of heparin with the Ca2+- and phospholipid-binding protein annexin II tetramer (AIIt). Analysis of the circular dichroism spectra demonstrated that the Ca2+-dependent binding of AIIt to heparin caused a large decrease in the α-helical content of...
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Veröffentlicht in: | The Journal of biological chemistry 1997-06, Vol.272 (24), p.15093-15100 |
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Sprache: | eng |
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Zusammenfassung: | In this report, we have characterized the interaction of heparin with the Ca2+- and phospholipid-binding protein annexin II tetramer (AIIt). Analysis of the circular dichroism spectra demonstrated that the Ca2+-dependent binding of AIIt to heparin caused a large decrease in the α-helical content of AIIt from ∼44 to 31%, a small decrease in the β-sheet content from ∼27 to 24%, and an increase in the unordered structure from 20 to 29%. The binding of heparin also decreased the Ca2+ concentration required for a half-maximal conformational change in AIIt from 360 to 84 μm. AIIt bound to heparin with an apparentKd of 32 ± 6 nm (mean ± S.D., n = 3) and a stoichiometry of 11 ± 0.9 mol of AIIt/mol of heparin (mean ± S.D., n = 3). The binding of heparin to AIIt was specific as other sulfated polysaccharides did not elicit a conformational change in AIIt. A region of the p36 subunit of AIIt (Phe306–Ser313) was found to contain a Cardin-Weintraub consensus sequence for glycosaminoglycan recognition. A peptide to this region underwent a conformational change upon heparin binding. Other annexins contained the Cardin-Weintraub consensus sequence, but did not undergo a substantial conformational change upon heparin binding. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.272.24.15093 |