title: Aberrant increase of NMR signal in hydrogen exchange experiments. Observation and explanation.
abstract: Hydrogen exchange (HX) NMR spectroscopy is widely used for monitoring structure, stability and dynamics of proteins at the level of individual residues. The stochastic replacement of protons by deuterons typically leads to an exponential decrease of the NMR signals. However, an unusual signal increase was observed in HX of several amides for T4 lysozyme L99A. This effect can be attributed to peak sharpening as a result of reduced dipolar relaxation from proximal amide protons that experience more rapid hydrogen/deuterium (H/D) exchange. The behavior was specifically observed at the termini of secondary structure elements, where large differences in protection against H/D exchange are observed. This effect is expected to be more widespread in NMR HX studies, and is important for the accurate determination of protection factors.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark.
authors.forename: Mengjun
authors.initials: M
authors.lastname: Xue
authors.affiliation: College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kitahara
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark. Electronic address: fmulder@chem.au.dk.
authors.forename: Frans A A
authors.initials: FA
authors.lastname: Mulder
mesh_terms: D041961:Deuterium Exchange Measurement; D006859:Hydrogen / Q000378:metabolism*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D012815:Signal Processing, Computer-Assisted
chemical_list: D006859:Hydrogen
keywords: Dipole-dipole interaction; Hydrogen/deuterium exchange; NMR spectroscopy; Protection factors; T4 lysozyme L99A