title: Site-specific analysis of heteronuclear Overhauser effects in microcrystalline proteins.
abstract: Relaxation parameters such as longitudinal relaxation are susceptible to artifacts such as spin diffusion, and can be affected by paramagnetic impurities as e.g. oxygen, which make a quantitative interpretation difficult. We present here the site-specific measurement of [(1)H](13)C and [(1)H](15)N heteronuclear rates in an immobilized protein. For methyls, a strong effect is expected due to the three-fold rotation of the methyl group. Quantification of the [(1)H](13)C heteronuclear NOE in combination with (13)C-R 1 can yield a more accurate analysis of side chain motional parameters. The observation of significant [(1)H](15)N heteronuclear NOEs for certain backbone amides, as well as for specific asparagine/glutamine sidechain amides is consistent with MD simulations. The measurement of site-specific heteronuclear NOEs is enabled by the use of highly deuterated microcrystalline protein samples in which spin diffusion is reduced in comparison to protonated samples.
authors.affiliation: Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching, Germany.
authors.forename: Juan Miguel Lopez
authors.initials: JM
authors.lastname: del Amo
authors.forename: Vipin
authors.initials: V
authors.lastname: Agarwal
authors.forename: Riddhiman
authors.initials: R
authors.lastname: Sarkar
authors.forename: Justin
authors.initials: J
authors.lastname: Porter
authors.forename: Sam
authors.initials: S
authors.lastname: Asami
authors.forename: Martin
authors.initials: M
authors.lastname: Rübbelke
authors.forename: Uwe
authors.initials: U
authors.lastname: Fink
authors.forename: Yi
authors.initials: Y
authors.lastname: Xue
authors.forename: Oliver F
authors.initials: OF
authors.lastname: Lange
authors.forename: Bernd
authors.initials: B
authors.lastname: Reif
mesh_terms: D000577:Amides / Q000737:chemistry; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry*; D002645:Chickens; D003460:Crystallization; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D013049:Spectrin / Q000737:chemistry*
chemical_list: D000577:Amides; D030161:Avian Proteins; D013049:Spectrin