Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 125, Issue 18, Pages 4714-4725Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.jpcb.1c01930
Keywords
-
Categories
Funding
- NSF [MCB1810695, DBI-2011234, MCB-1951425, CHE2003912]
- Intramural Research Program of the NIH, the National Heart, Lung, and Blood Institute
Ask authors/readers for more resources
This study optimized the parameters of menaquinone-8 and isoprenoid tail in archaeal membranes, and found that menaquinone-8 segregates to the membrane midplane above 10%, favoring an extended conformation in a fluid state. It was observed that menaquinone-8 increases bilayer thickness but does not significantly alter mechanical properties, and surprisingly increases water permeability by lowering the free energy barrier in the midplane. The study provides insights into the biophysical landscape of 50% menaquinone in archaeal bilayers and details about menaquinone configurations.
Halobacteria, a type of archaea in high salt environments, have phytanyl ether phospholipid membranes containing up to 50% menaquinone. It is not understood why a high concentration of menaquinone is required and how it influences membrane properties. In this study, menaquinone-8 headgroup and torsion parameters of isoprenoid tail are optimized in the CHARMM36 force field. Molecular dynamics simulations of archaeal bilayers containing 0 to 50% menaquinone characterize the distribution of menaquinone-8 and menaquinol-8, as well as their effects on mechanical properties and permeability. Menaquinone-8 segregates to the membrane midplane above concentrations of 10%, favoring an extended conformation in a fluid state. Menaquinone-8 increases the bilayer thickness but does not significantly alter the area compressibility modulus and lipid chain ordering. Counterintuitively, menaquinone-8 increases water permeability because it lowers the free energy barrier in the midplane. The thickness increase due to menaquinone-8 may help halobacteria ameliorate hyper-osmotic pressure by increasing the membrane bending constant. Simulations of the archaeal membranes with archaerhodopsin-3 show that the local membrane surface adjusts to accommodate the thick membranes. Overall, this study delineates the biophysical landscape of 50% menaquinone in the archaeal bilayer, demonstrates the mixing of menaquinone and menaquinol, and provides atomistic details about menaquinone configurations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available