A strategy for analyzing bond strength and interaction kinetics between Pleckstrin homology domains and PI(4,5)P2 phospholipids using force distance spectroscopy and surface plasmon resonance

Analyst. 2015 Jul 7;140(13):4558-65. doi: 10.1039/c5an00498e.

Abstract

Phospholipids are important membrane components involved in diverse biological activities ranging from cell signaling to infection by viral particles. A thorough understanding of protein-phospholipid interaction dynamics is thus crucial for deciphering basic cellular processes as well as for targeted drug discovery. For any specific phospholipid-protein binding experiment, various groups have reported different binding constants, which are strongly dependent on applied conditions of interactions. Here, we report a method for accurate determination of the binding affinity and specificity between proteins and phospholipids using a model interaction between PLC-δ1/PH and phosphoinositide phospholipid PtdIns(4,5)P2. We developed an accurate Force Distance Spectroscopy (FDS)-based assay and have attempted to resolve the problem of variation in the observed binding constant by directly measuring the bond force. We confirm the FDS findings of a high bond strength of ∼0.19 ± 0.04 nN by Surface Plasmon Resonance (SPR) data analysis, segregating non-specific interactions, which show a significantly lower K(D) suggesting tight binding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Proteins / chemistry*
  • Blood Proteins / metabolism*
  • Kinetics
  • Microscopy, Atomic Force / methods*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Phosphoproteins / chemistry*
  • Phosphoproteins / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Surface Plasmon Resonance / methods*

Substances

  • Blood Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphoproteins
  • platelet protein P47