Transforming growth factor receptor type II (ec-TβR II) behaves as a halophile

• Published in: International journal of biological macromolecules 2015-01, Vol.72, p.1104-1110
• Main Authors: Saini, Komal, Khan, M Ashhar I, Chakrapani, Sumit, Deep, Shashank
• Format: Article
• Language: English
• Subjects: Circular Dichroism; Hydrogen-Ion Concentration; Ions; Models, Molecular; Mutant Proteins - chemistry; Osmolar Concentration; Protein Denaturation - drug effects; Protein Stability - drug effects; Protein Structure, Secondary; Protein-Serine-Threonine Kinases - chemistry; Protein-Serine-Threonine Kinases - metabolism; Receptors, Transforming Growth Factor beta - chemistry; Receptors, Transforming Growth Factor beta - metabolism; Sodium Chloride - pharmacology; Spectrometry, Fluorescence; Static Electricity; Thermodynamics
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2014.09.051

The members of transforming growth factor β family (TGF-β) are multifunctional proteins but their main role is to control cell proliferation and differentiation. Polypeptides of TGF-β family function by binding to two related, functionally distinct transmembrane receptor kinases, first to the type II (TβR II) followed by type I receptor (TβR I). The paper describes, in details, the stability of wt-ec-TβR II under different conditions. The stability of wt-ec-TβR II was observed at different pH and salt concentration using fluorescence spectroscopy. Stability of ec-TβR II decreases with decrease in pH. Interestingly, the addition of salt increases the stability of the TβRII at pH 5.0 as observed for halophiles. Computational analysis using DELPHI suggests that this is probably due to the decrease in repulsion between negatively charged residues at surface on the addition of salt. This is further confirmed by the change in the stability of receptor on mutation of some of the residues (D32A) at surface.