Journal of Protein Chemistry

, Volume 16, Issue 4, pp 291–297

The Mechanism of 2,2,2-Trichloroacetic Acid-Induced Protein Precipitation

  • T. Sivaraman
  • T. K. S. Kumar
  • G. Jayaraman
  • C. Yu
Article

Abstract

The mechanism of 2,2,2-trichloroacetic acid (TCA)-induced precipitation of proteins is studied. The TCA-induced protein precipitation curves are observed to be U-shaped. It is bound that the protein-precipitate-inducing effects of TCA are due to the three chloro groups in the molecule. Using cardiotoxin III (CTX III) isolated from the Taiwan cobra (Naja naja atra), as a model protein, we attempt to understand the molecular basis for the TCA-induced effects. Employing circular dichroism, proton–deuterium exchange in conjunction with conventional 2D NMR techniques, and 1-anilino naphthalene-8-sulfonate-binding experiments, we demonstrate that CTX III is in a partially structured state similar to the ‘A state’ in 3% w/v TCA. It is postulated that the formation of this ‘sticky’ partial structured ‘A state’ in the TCA-induced unfolding pathway is responsible for the acid-induced protein precipitation.

A-state CTX III protein precipitation TCA 

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Copyright information

© Plenum Publishing Corporation 1997

Authors and Affiliations

  • T. Sivaraman
    • 1
  • T. K. S. Kumar
    • 1
  • G. Jayaraman
    • 1
  • C. Yu
    • 1
  1. 1.Department of ChemistryNational Tsing Hua UniversityHsinchuTaiwan

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