Measurement of dipolar cross-correlation in methylene groups in uniformly 13C-, 15N-labeled proteins.
A CC(CO)NH TOCSY-based 3D pulse scheme is presented for measuring (1)H-(13)C dipole-dipole cross-correlated relaxation at CH(2) positions in uniformly (13)C-, (15)N-labeled proteins. Simulations based on magnetization evolution under relaxation and scalar coupling interactions show that cross-correlation rates between (1)H-(13)C dipoles in CH(2) groups can be simply obtained from the intensities of (13)C triplets. The normalized cross-correlation relaxation rates are related to cross-correlation order parameters for macromolecules undergoing isotropic motion, which reflect the degrees of spatial restriction of CH(2) groups. The study on human intestinal fatty acid binding protein (131 residues) in the presence of oleic acid demonstrates that side chain dynamics at most CH(2) positions can be characterized for proteins less than 15 kDa in size, with the proposed TOCSY-based approach.
Zheng
Yu
Y
Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.
Yang
Daiwen
D
D002247:Carbon Isotopes; D002352:Carrier Proteins / Q000737:chemistry; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D006838:Hydrocarbons; D008239:Lysine / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry*; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*
D002247:Carbon Isotopes; D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D006838:Hydrocarbons; D009587:Nitrogen Isotopes; D011506:Proteins; C030011:carbene; D008239:Lysine; D008697:Methane