title: Selective observation of Asp and Glu resonances in (13)CO detected experiments.
abstract: We present a filter element to observe exclusively the resonances of Asp and Glu residues in several (13)C detected experiments, CACO, CBCACO, and CCCO. As in these experiments the carboxylate resonances appear in the directly detected dimension, it is possible to measure their chemical shifts with a high precision. Therefore, the experiments can be of great utility in the accurate determination of the pKa 's of these residues. Furthermore, the experiments can be applied in the study of deuterated proteins, where the usual experiments for pKa determination cannot be used. Finally, the good resolution with which the carboxylate spectrum is obtained allows observing the coupling between the carboxyl carbon and the backbone CO in Asp residues, what provides information on their side chain conformation.
authors.affiliation: Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Pantoja-Uceda
authors.forename: Jorge
authors.initials: J
authors.lastname: Santoro
mesh_terms: D001224:Aspartic Acid / Q000737:chemistry*; D002247:Carbon Isotopes; D018698:Glutamic Acid / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D025801:Ubiquitin; D001224:Aspartic Acid; D018698:Glutamic Acid