AI Article Synopsis
- The study examines how mercury exposure affects the structure of ovalbumin, leading to protein unfolding and the formation of aggregates.
- At increasing mercury concentrations (0-6.25 μM), ovalbumin initially associates into oligomers and then non-fibrillar aggregates, showing a three-stage transition characterized by a strong lag phase.
- Techniques like spectrophotometry and atomic force microscopy reveal toxic structural changes, including antiparallel β-sheets, highlighting how environmental toxins can switch protein conformation and potentially induce toxicity.
Article Abstract
Heavy metal based toxicity has a direct relation with the perturbation of protein structure. We have investigated the progressive unfolding of ovalbumin, in the presence of increasing concentration mercury (0-6.25 μM) using different spectroscopic techniques. Formation of amorphous aggregate has been observed at the physiological pH. Initial addition of HgCl resulted in the association of monomers to oligomers that proceeded to non-fibrillar aggregates on further addition. The sigmoidal curve obtained from the Stern-Volmer plot clearly divided into three stage transition. A strong lag phase is observed indicating the time dependence for the association of competent monomers. The second stage was resolved into non-cooperative binding. These results match very well with the data from atomic force microscopy and the free energy change observed in the regions. Raman spectroscopic studies indicated toxic antiparallel β-sheets structure. Time dependent atomic force microscopy study revealed the off-pathway nature of amorphous aggregates. At molten globular state, similar quenching behaviour is observed. The atomic force microscopy images clearly indicate at pH 2.2 the initiation of fibril formation occurs at lower concentration of HgCl itself. Our results revealed the conformation switch of ovalbumin upon the contact of an environmental toxin and its possible way of toxicity.
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| http://dx.doi.org/10.1016/j.ijbiomac.2021.01.134 | DOI Listing |
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