Refolding of urea denatured cytochrome c: Role of hydrophobic tail of the cationic gemini surfactants.
The refolding of urea denatured horse heart cytochrome c (h-cyt-c) under the influence of ester based cationic gemini surfactants [ethane-1, 2-diyl bis(N, N-dimethyl-N-alkylammoniumacetoxy) dichlorides] 16-E2-16, 14-E2-14 and 12-E2-12 (n-E2-n) was performed by using UV-visible, fluorescence and circular dichroism (CD) spectroscopic techniques. We found that n-E2-n geminis promote the formation of molten globule (MG) like state upon addition into the urea denatured h-cyt-c. The comparative study of refolding of denatured h-cyt-c with n-E2-n, cationic gemini surfactant show stabilization of MG-like state influenced by hydrophobic interactions. The formation of MG-like state from the unfolded protein confirms the presence of some regular structures induced by n-E2-n gemini surfactants. Thermodynamic parameters for refolding of h-cyt-c by n-E2-n were also measured and the m-values of all the refolded states of h-cyt-c by n-E2-n show marked difference. The higher m-values correspond to the larger hydrophobic chain length indicates that refolding ability of the n-E2-n depends on the alkyl chain length. The result is related to the stronger hydrophobic forces due to the presence of two head groups and two hydrophobic hydrocarbon tails. This study showed that these cationic gemini surfactants were efficiently utilized in the protein refolding studies.
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India. Electronic address: rajanpatelpcy@gmail.com.
Rajan
R
Patel
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India.
Muzaffar Ul Hassan
MUH
Mir
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India.
Upendra Kumar
UK
Singh
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India.
Ilyas
I
Beg
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India.
Asimul
A
Islam
Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (A Central University), New Delhi, India.
Abbul Bashar
AB
Khan
D000818:Animals; D045304:Cytochromes c / Q000737:chemistry*; D006736:Horses; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D009206:Myocardium / Q000737:chemistry / Q000201:enzymology; D011489:Protein Denaturation; D058849:Protein Refolding; D017433:Protein Structure, Secondary; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014508:Urea / Q000737:chemistry*
D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014508:Urea; D045304:Cytochromes c
Cationic gemini surfactants; Horse heart cytochrome c; Hydrophobic interactions; Molten globule-like state; Protein folding