2,4-Dinitrophenol’s (2,4-DNP) effect on synthetic membrane proteins was investigated to test if i... more 2,4-Dinitrophenol’s (2,4-DNP) effect on synthetic membrane proteins was investigated to test if it is selective to cancer-mimic synthetic cell membranes, which are more bountiful in phosphatidylserine (PS) lipids compared to normal cells that have much more phosphatidylcholine (PC) lipids. Three undergraduate students prepared the untreated synthetic membranes and incorporated 2,4-DNP into a second set of treated samples. Students analysed the samples via solid-state 31P NMR. The results indicate that 2,4-DNP breaks down 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-L-serine] (POPS) synthetic membranes, but not 1-palmitoyl-2-oleoyl -sn-glycero-3-phosphocholine (POPC) membranes that mimic the normal cell membrane composition. The 31P NMR spectrum of the head groups of the membrane suggests that the 2,4-DNP is disturbing the multilamellar vesicles (MLVs) and forming small micelles only in the POPS synthetic membranes.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2021
There have recently been advances in methods for detecting local secondary structures of membrane... more There have recently been advances in methods for detecting local secondary structures of membrane protein using electron paramagnetic resonance (EPR). A three pulsed electron spin echo envelope modulation (ESEEM) approach was used to determine the local helical secondary structure of the small hole forming membrane protein, S21 pinholin. This ESEEM approach uses a combination of site-directed spin labeling and 2H-labeled side chains. Pinholin S21 is responsible for the permeabilization of the inner cytosolic membrane of double stranded DNA bacteriophage host cells. In this study, we report on the overall global helical structure using circular dichroism (CD) spectroscopy for the active form and the negative-dominant inactive mutant form of S21 pinholin. The local helical secondary structure was confirmed for both transmembrane domains (TMDs) for the active and inactive S21 pinholin using the ESEEM spectroscopic technique. Comparison of the ESEEM normalized frequency domain intensity for each transmembrane domain gives an insight into the α-helical folding nature of these domains as opposed to a π or 310-helix which have been observed in other channel forming proteins.
2,4-Dinitrophenol’s (2,4-DNP) effect on synthetic membrane proteins was investigated to test if i... more 2,4-Dinitrophenol’s (2,4-DNP) effect on synthetic membrane proteins was investigated to test if it is selective to cancer-mimic synthetic cell membranes, which are more bountiful in phosphatidylserine (PS) lipids compared to normal cells that have much more phosphatidylcholine (PC) lipids. Three undergraduate students prepared the untreated synthetic membranes and incorporated 2,4-DNP into a second set of treated samples. Students analysed the samples via solid-state 31P NMR. The results indicate that 2,4-DNP breaks down 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-L-serine] (POPS) synthetic membranes, but not 1-palmitoyl-2-oleoyl -sn-glycero-3-phosphocholine (POPC) membranes that mimic the normal cell membrane composition. The 31P NMR spectrum of the head groups of the membrane suggests that the 2,4-DNP is disturbing the multilamellar vesicles (MLVs) and forming small micelles only in the POPS synthetic membranes.
Biochimica et Biophysica Acta (BBA) - Biomembranes, 2021
There have recently been advances in methods for detecting local secondary structures of membrane... more There have recently been advances in methods for detecting local secondary structures of membrane protein using electron paramagnetic resonance (EPR). A three pulsed electron spin echo envelope modulation (ESEEM) approach was used to determine the local helical secondary structure of the small hole forming membrane protein, S21 pinholin. This ESEEM approach uses a combination of site-directed spin labeling and 2H-labeled side chains. Pinholin S21 is responsible for the permeabilization of the inner cytosolic membrane of double stranded DNA bacteriophage host cells. In this study, we report on the overall global helical structure using circular dichroism (CD) spectroscopy for the active form and the negative-dominant inactive mutant form of S21 pinholin. The local helical secondary structure was confirmed for both transmembrane domains (TMDs) for the active and inactive S21 pinholin using the ESEEM spectroscopic technique. Comparison of the ESEEM normalized frequency domain intensity for each transmembrane domain gives an insight into the α-helical folding nature of these domains as opposed to a π or 310-helix which have been observed in other channel forming proteins.
Uploads