02444nas a2200229   4500008004100000022001400041245016500055210006900220260007400289300001200363490000700375520151400382653003701896653003801933653002201971653003101993653000802024100002202032700001202054700001902066856012902085       2005                        eng d  a0925-273800aDetermination of C-13 CSA tensors: extension of the model-independent approach to an RNA kissing complex undergoing anisotropic rotational diffusion in solution0 aDetermination of C13 CSA tensors extension of the modelindepende  aVAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDSbSPRINGERcNOV  a163-1740 v333 a<p>Chemical shift anisotropy (CSA) tensor parameters have been determined for the protonated carbons of the purine bases in an RNA kissing complex in solution by extending the model-independent approach [Fushman, D., Cowburn, D. (1998) J. Am. Chem. Soc. 120, 7109-7110]. A strategy for determining CSA tensor parameters of heteronuclei in isolated X-H two-spin systems (X = C-13 or N-15) in molecules undergoing anisotropic rotational diffusion is presented. The original method relies on the fact that the ratio kappa(2)=R-2(auto)/R-2(cross) of the transverse auto- and cross-correlated relaxation rates involving the X CSA and the X-H dipolar interaction is independent of parameters related to molecular motion, provided rotational diffusion is isotropic. However, if the overall motion is anisotropic kappa(2) depends on the anisotropy D parallel to/D-perpendicular to of rotational diffusion. In this paper, the field dependence of both kappa(2) and its longitudinal counterpart kappa(1)=R-1(auto)/R-1(cross) are determined. For anisotropic rotational diffusion, our calculations show that the average kappa(av) = 1/2 (kappa(1)+kappa(2)), of the ratios is largely independent of the anisotropy parameter D parallel to/D-perpendicular to. The field dependence of the average ratio kappa(av) may thus be utilized to determine CSA tensor parameters by a generalized model-independent approach in the case of molecules with an overall motion described by an axially symmetric rotational diffusion tensor.</p>10aanisotropic rotational diffusion10achemical shift anisotropy tensors10across-correlation10amodel-independent approach10aNMR1 aRavindranathan, S1 aKim, CH1 aBodenhausen, G  uhttps://library.ncl.res.in/content/determination-c-13-csa-tensors-extension-model-independent-approach-rna-kissing-complex-1