Interaction of iodoacetamidofluorescein‐labelled tropomyosin with deoxyribonuclease I

FEBS Letters

Burtnick, L.D.¹  Wong, M.K.C.¹ 

[1] Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Y6, Canada

关键词: Tropomyosin;    Deoxyribonuclease I;    Fluorescence polarization;    Fluorescence quenching;    IAF;    5-iodoacetamidofluorescein;    TM;    tropomyosin;    DNase I;    deoxyribonuclease I;    DTT;    DL-dithiothreitol;    Mops;    3-(N-morpholino)propanesulfonic acid;   

DOI  :  10.1016/0014-5793(89)80554-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

5-Iodoacetamidofluorescein (IAF) reacted with rabbit cardiac muscle tropomyosin (TM) to yield a highly fluorescent product, IAF-TM. The extent of labelling reached one fluorescein group per TM molecule in solutions at pH 8.5. While fluorescence polarization values for IAF-TM solutions were unaffected by the presence or absence of KCl, addition of pancreatic deoxyribonuclease I (DNase I) resulted in a 10% drop, suggestive of a greater freedom of motion of the fluorescein label in the presence of DNase I. Furthermore, a 15% increase in slopes of Stern-Volmer plots for IAF-TM in the presence of DNase I demonstrated a greater susceptibility of the fluorescein group to dynamic quenching by iodide. These results suggest that interaction between DNase I and TM produces a localized unfolding of the coiled coil near the IAF reactive site on TM.

【 授权许可】

Unknown