Stopped‐flow fluorescence kinetic studies of Glu‐plasminogen Conformational changes triggered by AH‐site ligand binding

FEBS Letters

Molgaard, Lone¹  Christensen, Ulla¹ 

[1] Chemical Laboratory IV, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark

关键词: Stopped-flow fluorescence;    Glu-plasminogen;    AH-site;    6-Aminohexanoic acid;    Conformational change: Plasminogen activation;   

DOI  :  10.1016/0014-5793(91)80117-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Binding of 6-aminohexanoic acid to the AH-site, a weak lysine binding site in Glu-plasminogen, alters the conformation of the molecule. The kinetics of the binding and the accompanying conformational change are investigated at pH 7.8. 25°C. Changes of intrinsic protein fluorescence were measured as a function of time after rapid mixing in a stopped-flow apparatus. The results reflect a two-step reaction mechanism: Rapid association of Glu-plasminogen and 6-aminohexanoic acid (K ₁ = 44 mM) followed by the conformational change (k ₂ = 69 g⁻¹ and k ₋₂ = 3 g⁻¹) with on overall dissociation constant K ₄ = 2.0 mM, Thus the conformational change is rather fast, t = 0.01 g. Its importance for the rates or Glu-plasminogen activation reactions is discussed.

【 授权许可】

Unknown