The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jagdish K Vij - One of the best experts on this subject based on the ideXlab platform.
-
unexpected electric field induced antiferroelectric liquid crystal phase in the sm c α temperature range and the discrete flexoelectric effect
Physical Review E, 2019Co-Authors: Yoichi Takanishi, M A Osipov, Atsuo Iida, Neelam Yadav, Atsuo Fukuda, A Chandani D L Perera, Jagdish K VijAbstract:The unique nanometer-sized Helical Structure in SmC_{α}^{*} may sometimes evolve continuously to the micrometer-sized one in SmC^{*}; conceivably ferroelectric SmC_{α}^{*} is to be unwound by an applied electric field. By drawing electric-field-induced birefringence contours in the field-temperature phase diagram and by studying the superlattice Structure of the field-induced subphase with resonant x-ray scattering, we established that an applied field unexpectedly stabilizes the well-known antiferroelectric four-layer biaxial subphase as well as the other prototypal ferrielectric three-layer one in the SmC_{α}^{*} temperature range; the effective long-range interlayer interaction due to the discrete flexoelectric effect actually plays an important role in stabilizing not only the biaxial subphases but also the optically uniaxial SmC_{α}^{*} subphase, contrary to the notion that the competition between the direct interactions of the nearest-neighbor layers and those of the next-nearest-neighbor layers should be required for the nanometer-sized Helical Structure.
Alexander E Conicella - One of the best experts on this subject based on the ideXlab platform.
-
tdp 43 α Helical Structure tunes liquid liquid phase separation and function
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Alexander E Conicella, Gregory L Dignon, Gul H Zerze, Hermann Broder Schmidt, Alexandra M Dordine, Young C Kim, Rajat RohatgiAbstract:Liquid–liquid phase separation (LLPS) is involved in the formation of membraneless organelles (MLOs) associated with RNA processing. The RNA-binding protein TDP-43 is present in several MLOs, undergoes LLPS, and has been linked to the pathogenesis of amyotrophic lateral sclerosis (ALS). While some ALS-associated mutations in TDP-43 disrupt self-interaction and function, here we show that designed single mutations can enhance TDP-43 assembly and function via modulating Helical Structure. Using molecular simulation and NMR spectroscopy, we observe large structural changes upon dimerization of TDP-43. Two conserved glycine residues (G335 and G338) are potent inhibitors of Helical extension and helix–helix interaction, which are removed in part by variants at these positions, including the ALS-associated G335D. Substitution to helix-enhancing alanine at either of these positions dramatically enhances phase separation in vitro and decreases fluidity of phase-separated TDP-43 reporter compartments in cells. Furthermore, G335A increases TDP-43 splicing function in a minigene assay. Therefore, the TDP-43 Helical region serves as a short but uniquely tunable module where application of biophysical principles can precisely control assembly and function in cellular and synthetic biology applications of LLPS.
-
tdp 43 α Helical Structure tunes liquid liquid phase separation and function
bioRxiv, 2019Co-Authors: Alexander E Conicella, Gregory L Dignon, Gul H Zerze, Hermann Broder Schmidt, Alexandra M Dordine, Young C Kim, Rajat Rohatgi, Yuna M Ayala, Jeetain Mittal, Nicolas L FawziAbstract:Liquid-liquid phase separation (LLPS) is involved in the formation of membraneless organelles (MLOs) associated with RNA processing. Present in several MLOs, TDP-43 undergoes LLPS and is linked to the pathogenesis of amyotrophic lateral sclerosis (ALS). While some disease variants of TDP-43 disrupt self-interaction and function, here we show that designed single mutations can enhance TDP-43 assembly and function via modulating Helical Structure. Using molecular simulation and NMR spectroscopy, we observe large structural changes in a dimeric TDP-43. Two conserved glycine residues (G335 and G338) are potent inhibitors of Helical extension and helix-helix interaction, which are removed in part by variants including the ALS-associated G335D. Substitution to helix-enhancing alanine at either of these positions dramatically enhances phase separation in vitro and decreases fluidity of phase separated TDP-43 reporter compartments in cells. Furthermore, G335A increases TDP-43 splicing function in a mini-gene assay. Therefore, TDP-43 Helical region serves as a short but uniquely tunable module that shows promise as for controlling assembly and function in cellular and synthetic biology applications of LLPS.
Yoichi Takanishi - One of the best experts on this subject based on the ideXlab platform.
-
unexpected electric field induced antiferroelectric liquid crystal phase in the sm c α temperature range and the discrete flexoelectric effect
Physical Review E, 2019Co-Authors: Yoichi Takanishi, M A Osipov, Atsuo Iida, Neelam Yadav, Atsuo Fukuda, A Chandani D L Perera, Jagdish K VijAbstract:The unique nanometer-sized Helical Structure in SmC_{α}^{*} may sometimes evolve continuously to the micrometer-sized one in SmC^{*}; conceivably ferroelectric SmC_{α}^{*} is to be unwound by an applied electric field. By drawing electric-field-induced birefringence contours in the field-temperature phase diagram and by studying the superlattice Structure of the field-induced subphase with resonant x-ray scattering, we established that an applied field unexpectedly stabilizes the well-known antiferroelectric four-layer biaxial subphase as well as the other prototypal ferrielectric three-layer one in the SmC_{α}^{*} temperature range; the effective long-range interlayer interaction due to the discrete flexoelectric effect actually plays an important role in stabilizing not only the biaxial subphases but also the optically uniaxial SmC_{α}^{*} subphase, contrary to the notion that the competition between the direct interactions of the nearest-neighbor layers and those of the next-nearest-neighbor layers should be required for the nanometer-sized Helical Structure.
Martin Schoen - One of the best experts on this subject based on the ideXlab platform.
-
flow assisted self healing of the Helical Structure in a cholesteric liquid crystal
Journal of Chemical Physics, 2021Co-Authors: Janchristoph Eichler, Robert A Skutnik, Marco G Mazza, Martin SchoenAbstract:We employ nonequilibrium molecular dynamics simulations to investigate the Structure and dynamics of a cholesteric liquid crystal confined between atomically corrugated solid walls. By choosing walls normal to the Helical axis, we can study systems with an arbitrary cholesteric pitch without exposing the cholesteric helix to a spurious stress. We investigate the effects of local heating and flow and their joint effects. A steady-state laminar Poiseuille flow is initiated by means of an external body force. Flow alone (i.e., without local heating) in a direction normal to the Helical axis does not affect the cholesteric pitch. If the liquid crystal is heated in a small region, the cholesteric helix becomes unstable and melts locally. However, if local heating and flow are combined, a nontrivial synergistic effect is observed in that the Helical Structure recuperates the better, the higher the speed of the flow is.
Rajat Rohatgi - One of the best experts on this subject based on the ideXlab platform.
-
tdp 43 α Helical Structure tunes liquid liquid phase separation and function
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Alexander E Conicella, Gregory L Dignon, Gul H Zerze, Hermann Broder Schmidt, Alexandra M Dordine, Young C Kim, Rajat RohatgiAbstract:Liquid–liquid phase separation (LLPS) is involved in the formation of membraneless organelles (MLOs) associated with RNA processing. The RNA-binding protein TDP-43 is present in several MLOs, undergoes LLPS, and has been linked to the pathogenesis of amyotrophic lateral sclerosis (ALS). While some ALS-associated mutations in TDP-43 disrupt self-interaction and function, here we show that designed single mutations can enhance TDP-43 assembly and function via modulating Helical Structure. Using molecular simulation and NMR spectroscopy, we observe large structural changes upon dimerization of TDP-43. Two conserved glycine residues (G335 and G338) are potent inhibitors of Helical extension and helix–helix interaction, which are removed in part by variants at these positions, including the ALS-associated G335D. Substitution to helix-enhancing alanine at either of these positions dramatically enhances phase separation in vitro and decreases fluidity of phase-separated TDP-43 reporter compartments in cells. Furthermore, G335A increases TDP-43 splicing function in a minigene assay. Therefore, the TDP-43 Helical region serves as a short but uniquely tunable module where application of biophysical principles can precisely control assembly and function in cellular and synthetic biology applications of LLPS.
-
tdp 43 α Helical Structure tunes liquid liquid phase separation and function
bioRxiv, 2019Co-Authors: Alexander E Conicella, Gregory L Dignon, Gul H Zerze, Hermann Broder Schmidt, Alexandra M Dordine, Young C Kim, Rajat Rohatgi, Yuna M Ayala, Jeetain Mittal, Nicolas L FawziAbstract:Liquid-liquid phase separation (LLPS) is involved in the formation of membraneless organelles (MLOs) associated with RNA processing. Present in several MLOs, TDP-43 undergoes LLPS and is linked to the pathogenesis of amyotrophic lateral sclerosis (ALS). While some disease variants of TDP-43 disrupt self-interaction and function, here we show that designed single mutations can enhance TDP-43 assembly and function via modulating Helical Structure. Using molecular simulation and NMR spectroscopy, we observe large structural changes in a dimeric TDP-43. Two conserved glycine residues (G335 and G338) are potent inhibitors of Helical extension and helix-helix interaction, which are removed in part by variants including the ALS-associated G335D. Substitution to helix-enhancing alanine at either of these positions dramatically enhances phase separation in vitro and decreases fluidity of phase separated TDP-43 reporter compartments in cells. Furthermore, G335A increases TDP-43 splicing function in a mini-gene assay. Therefore, TDP-43 Helical region serves as a short but uniquely tunable module that shows promise as for controlling assembly and function in cellular and synthetic biology applications of LLPS.