Abstract
Chromatin has been introduced as a tool for studying heavy metals action in nuclei. Chromium oxide is highly soluble and toxic with chronic exposure leading to mutagenesis and carcinogenesis. In the present study, for the first time, the binding affinity of chromium oxide to rat liver chromatin and histone proteins was investigated. Reduction of chromatin absorbencies at 210 and 260nm (hypochromicity) and fluorescence emission intensity upon metal binding represented quenching of the metal with chromatin chromophores. Binding isotherms demonstrated a positive cooperative binding pattern revealing higher affinity of the metal to chromatin compared to DNA as confirmed by the binding constants. Melting temperature of chromatin was altered in a dose dependent manner and suggests partial removal of histones from the chromatin at metal concentrations higher than 15μg/ml. Chromium oxide decreased the absorbance of histone H1 at 210nm (hypochromicity) and fluorescence emission intensity revealed quenching of the metal with tyrosine residue located in the core domain of H1. Also the interaction of chromium oxide with histone H1 increased its secondary structures. The results suggest toxic effect of very low concentrations of chromium oxide on chromatin and in this reaction both DNA and histones are involved.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Biological Macromolecules
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
