title: Facilitating unambiguous NMR assignments and enabling higher probe density through selective labeling of all methyl containing amino acids.
abstract: The deuteration of proteins and selective labeling of side chain methyl groups has greatly enhanced the molecular weight range of proteins and protein complexes which can be studied using solution NMR spectroscopy. Protocols for the selective labeling of all six methyl group containing amino acids individually are available, however to date, only a maximum of five amino acids have been labeled simultaneously. Here, we describe a new methodology for the simultaneous, selective labeling of all six methyl containing amino acids using the 115 kDa homohexameric enzyme CoaD from E. coli as a model system. The utility of the labeling protocol is demonstrated by efficiently and unambiguously assigning all methyl groups in the enzymatic active site using a single 4D (13)C-resolved HMQC-NOESY-HMQC experiment, in conjunction with a crystal structure. Furthermore, the six fold labeled protein was employed to characterize the interaction between the substrate analogue (R)-pantetheine and CoaD by chemical shift perturbations, demonstrating the benefit of the increased probe density.
authors.affiliation: Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, CA, 94608, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Proudfoot
authors.affiliation: Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, CA, 94608, USA.
authors.forename: Andreas O
authors.initials: AO
authors.lastname: Frank
authors.affiliation: Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, CA, 94608, USA.
authors.forename: Fiorella
authors.initials: F
authors.lastname: Ruggiu
authors.affiliation: Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, CA, 94608, USA.
authors.forename: Mulugeta
authors.initials: M
authors.lastname: Mamo
authors.affiliation: Novartis Institutes for BioMedical Research, 5300 Chiron Way, Emeryville, CA, 94608, USA. andreas.lingel@novartis.com.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lingel
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular; D009713:Nucleotidyltransferases / Q000737:chemistry; D013194:Staining and Labeling
chemical_list: D000596:Amino Acids; D029968:Escherichia coli Proteins; D009713:Nucleotidyltransferases; C022315:pantetheine-phosphate adenylyltransferase
keywords: 4D NOESY; Assignments; CoaD; Methyl groups; NMR; Selective labeling