title: Stereospecific assignments of the leucine methyl resonances in the 1H NMR spectrum of Lactobacillus casei dihydrofolate reductase.
abstract: A general method is described for the stereospecific assignment of methyl resonances in protein NMR spectra based on selective deuteration procedures. A selectively deuterated dihydrofolate reductase from L. casei was prepared by incorporating stereoselectively deuterated L-leucine, (2S,4R)[5,5,5-2H3]leucine. By comparing the COSY spectra of the dihydrofolate reductase-methotrexate complexes formed using deuterated and non-deuterated enzyme the stereospecific assignments for resonances of all 13 leucine residues were obtained by noting the absence of cross-peaks in spectra from the deuterated proteins.
authors.affiliation: Laboratory of Molecular Structure, National Institute for Medical Research, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Ostler
authors.forename: A
authors.initials: A
authors.lastname: Soteriou
authors.forename: C M
authors.initials: CM
authors.lastname: Moody
authors.forename: J A
authors.initials: JA
authors.lastname: Khan
authors.forename: B
authors.initials: B
authors.lastname: Birdsall
authors.forename: M D
authors.initials: MD
authors.lastname: Carr
authors.forename: D W
authors.initials: DW
authors.lastname: Young
authors.forename: J
authors.initials: J
authors.lastname: Feeney
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D007780:Lacticaseibacillus casei / Q000201:enzymology*; D007930:Leucine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism; D013762:Tetrahydrofolate Dehydrogenase / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D013762:Tetrahydrofolate Dehydrogenase; D007930:Leucine