Stereospecific assignments of the leucine methyl resonances in the 1H NMR spectrum of Lactobacillus casei dihydrofolate reductase.
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.
Ostler
G
G
Laboratory of Molecular Structure, National Institute for Medical Research, London, UK.
Soteriou
A
A
Moody
C M
CM
Khan
J A
JA
Birdsall
B
B
Carr
M D
MD
Young
D W
DW
Feeney
J
J
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*
D001426:Bacterial Proteins; D013762:Tetrahydrofolate Dehydrogenase; D007930:Leucine