Stereogenic Elements, Chirotopicity, Permutational Isomers, and Gear-Like Correlated Motion of Molecular Subunits

2015 ◽  
pp. 113-126
Keyword(s):  
Correlated Motion

scholarly journals Crystalline Arrays of Pairs of Molecular Rotors: Correlated Motion, Rotational Barriers, and Space-Inversion Symmetry Breaking Due to Conformational Mutations

2013 ◽  
Vol 135 (25) ◽  
pp. 9366-9376 ◽  
Author(s):  
Cyprien Lemouchi ◽  
Konstantinos Iliopoulos ◽  
Leokadiya Zorina ◽  
Sergey Simonov ◽  
Pawel Wzietek ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Molecular Rotors ◽  
Inversion Symmetry ◽  
Rotational Barriers ◽  
Correlated Motion ◽  
Space Inversion

scholarly journals Nucleolar dynamics and interactions with nucleoplasm in living cells

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Christina M Caragine ◽  
Shannon C Haley ◽  
Alexandra Zidovska
Keyword(s):  
Current Theory ◽  
Living Cells ◽  
Volume Distribution ◽  
Liquid Droplets ◽  
Nucleolar Volume ◽  
Correlated Motion ◽  
The Impact ◽  
Surrounding Liquid ◽  
Organizing Principles

Liquid-liquid phase separation (LLPS) has been recognized as one of the key cellular organizing principles and was shown to be responsible for formation of membrane-less organelles such as nucleoli. Although nucleoli were found to behave like liquid droplets, many ramifications of LLPS including nucleolar dynamics and interactions with the surrounding liquid remain to be revealed. Here, we study the motion of human nucleoli in vivo, while monitoring the shape of the nucleolus-nucleoplasm interface. We reveal two types of nucleolar pair dynamics: an unexpected correlated motion prior to coalescence and an independent motion otherwise. This surprising kinetics leads to a nucleolar volume distribution, p⁢(V)∼V-1, unaccounted for by any current theory. Moreover, we find that nucleolus-nucleoplasm interface is maintained by ATP-dependent processes and susceptible to changes in chromatin transcription and packing. Our results extend and enrich the LLPS framework by showing the impact of the surrounding nucleoplasm on nucleoli in living cells.

Molecular Motion in Tetraphenyltin Studied by NMR

1999 ◽  
Vol 54 (8-9) ◽  
pp. 488-494
Author(s):  
A. Pajzderska ◽  
J. Wąsicki ◽  
S. Lewicki
Keyword(s):  
Phenyl Ring ◽  
Room Temperature ◽  
Molecular Motion ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Ring Rotation ◽  
Phenyl Rings ◽  
Correlated Motion

NMR second moment and spin-lattice relaxation times in the laboratory (60 and 25 MHz) and in therotating frame (B1 = 2.1 mT) were studied for polycrystalline tetraphenyltin Sn(C6H5)4 in a wide temperaturerange. Two kinds of motions were detected: isotropic rotation of whole molecules and reorientations/oscillations of phenyl rings. A dependence of the potential energy of the molecule in the crystalon the angle of the phenyl ring rotation about the Sn-C bond was obtained on the basis of atom-atomcalculations. The amplitude of the ring-oscillations at 133 K was estimated as ± 7°. Below room temperaturethe magnetisation recovery is significantly non-exponential, which may be interpreted as dueto the correlated motion of phenyl rings.

scholarly journals Correlated Motion and Oscillation of Neighboring Cells in Vitro

2001 ◽  
Vol 8 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Chun-Min Lo ◽  
Michael Linton ◽  
Charles R. Keese ◽  
Ivar Giaever
Keyword(s):  
Correlated Motion

Nuclear magnetic resonance studies of the methylammonium hexahalotellurates

1992 ◽  
Vol 70 (3) ◽  
pp. 849-855 ◽  
Author(s):  
Mark R. MacIntosh ◽  
Marco L. H. Gruwel ◽  
Katherine N. Robertson ◽  
Roderick E. Wasylishen
Keyword(s):  
Line Shape ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Solid Phase ◽  
Variable Temperature ◽  
Spin Lattice Relaxation ◽  
Temperature Phase ◽  
H Nmr ◽  
Nmr Study ◽  
Correlated Motion

A 2H and 14N NMR study of the solid methylammonium hexahalotellurates, (MA)2TeX6 (MA = CH3ND3+ or CD3NH3+, X = Cl, Br, and I), has been undertaken to characterize the dynamics of the methylammonium (MA) ion as a function of temperature. At room temperature, the MA ion in the hexachlorotellurate (solid II) is confined to C3 jumps about the C—N axis while a small angle libration of the C—N axis is occurring. In the room temperature phase, solid I, of (MA)2TeBr6 and (MA)2TeI6 the MA ions are performing overall reorientations on the ps time scale, averaging the 2H nuclear quadrupolar interactions to zero. Variable temperature 2H NMR spin-lattice relaxation times, T1, indicate an activation energy, EA, for "isotropic" reorientations of the CH3ND3+ ion of 5.2 ± 0.5 and 2.6 ± 0.3 kJ mol−1 for X = Br and I, respectively. Deuterium T1 values for C-deuterated MA ion in the hexaiodotellurate indicate an EA for whole-ion reorientation of 3.1 ± 0.3 kJ mol−1. At any given temperature, the correlation time, τc, derived from the T1 results was found to be the same for the two deuterium-labelled hexaiodotellurates. The similarity of both the EA and the τc values implies correlated motion of the methyl and ammonium groups. The 14N T1 results for solid I of (MA)2TeI6 indicate that C—N axis motions, with an EA = 5.6 ± 0.6 kJ mol−1, are more hindered than N—D or C—D bond dynamics. The 2H NMR spectra for (MA)2TeI6 (solid II) and (MA)2TeBr6 (solids II, III, and IV) are characterized by a Pake doublet line shape. The measured peak-to-peak splittings are less than what is predicted by C3 motion about the molecular symmetry axis. It is possible to model these line shapes by postulating that C3 rotations of the methyl and ammonium groups occur as the C—N axis librates in an effective cone about the position of the static molecular axis. For (CH3ND3)2TeBr6 and (CD3NH3)3TeBr6 the peak-to-peak splittings in the 2H NMR spectra were measured as a function of temperature in solid phases II, III, and IV and were found to be similar. Finally, the 2H NMR line shape relaxation for (MA)2TeBr6 (solid III) displays an orientation dependence indicating that rotations about the C—N axis are discrete rather than diffusive in nature. For solid phase II of (MA)2TeCl6, the line shape is observed to relax isotropically, implying that continuous C3 rotations are taking place. Keywords: 2H and 14N NMR, methylammonium hexahalotellurates, molecular motion.

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