DSpace Repository

Ultrafast Heme Relaxation Dynamics Probing the Unfolded States of Cytochrome c Induced by Liposomes: Effect of Charge of Phospholipids

Show simple item record

dc.contributor.author GOVIND, C
dc.contributor.author PAUL, M
dc.contributor.author KARUNAKARAN, V
dc.date.accessioned 2021-04-30T05:43:07Z
dc.date.available 2021-04-30T05:43:07Z
dc.date.issued 2020-04-09
dc.identifier.citation The Journal of Physical Chemistry B;124(14):2769-2777 en_US
dc.identifier.uri https://doi.org/10.1021/acs.jpcb.9b11957
dc.identifier.uri http://hdl.handle.net/123456789/3727
dc.description.abstract The ubiquitous electron transfer heme protein, Cytochrome c (Cyt c) catalyzes the peroxidation of cardiolipin (CL) in the early stage of apoptosis, where Cyt c undergoes conformational changes leading to the partial unfolding of the protein. Here the interaction dynamics of Cyt c with liposomes having different charges [CL, – 2; POPG (2-Oleoyl-1-palmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt), −1; and POPC (2-Oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine), 0] leading to various degrees of partial unfolding is investigated with steady state optical spectroscopy and femtosecond time-resolved pump–probe spectroscopy. The signature of the partial unfolding of the protein was observed in the absorption, fluorescence, and CD spectra of Cyt c–liposome complexes with an increase of lipid/protein (L/P) ratio, and the protein was refolded by the addition of 0.1 M of NaCl. The femtosecond transient absorption spectra of the complexes were measured by selectively exciting the heme and tryptophan (Trp) at 385 and 280 nm, respectively. Though significant changes were not observed in the excited state relaxation dynamics of the heme in liposomes by exciting at 385 nm, the 280 nm excitation exhibited a systematic increase of the excited state relaxation dynamics leading to the increase of lifetime of Trp and global conformational relaxation dynamics with the increase of anionic charge of the lipids. This reveals the decrease of efficiency of fluorescence resonance energy transfer from Trp to heme due to the increase of distance between them upon increase of partial unfolding of the proteins by liposomes. Such observation exhibits the Trp as a marker amino acid to reflect the dynamics of partial unfolding of the protein rising from the change in the tertiary structure and axial ligand interaction of the heme proteins in liposomes. The relaxation dynamics of the complexes in the presence of salt are similar to that of the protein alone, reflecting that the refolding of the protein and the interactions are dominated by electrostatic interaction rather than the hydrophobic interaction. en_US
dc.language.iso en en_US
dc.publisher American Chemical Society en_US
dc.subject cytochrome en_US
dc.subject liposomes en_US
dc.subject phospholipids en_US
dc.title Ultrafast Heme Relaxation Dynamics Probing the Unfolded States of Cytochrome c Induced by Liposomes: Effect of Charge of Phospholipids en_US
dc.type Article en_US


Files in this item

This item appears in the following Collection(s)

  • 2020
    Research articles authored by NIIST researchers published in 2020

Show simple item record

Search DSpace


Advanced Search

Browse

My Account