Solid-state NMR and density functional theory studies of ionization states of thiamin.

ABSTRACT: Thiamin diphosphate (ThDP) is a key coenzyme in sugar metabolism. The 4'-aminopyrimidine ring of ThDP cycles through several ionization and tautomeric states during enzyme catalysis, but it is not fully understood which states are adopted during the individual steps of the catalytic cycle. Thiamin has been synthesized with labels selectively inserted into the C2 and C6' positions, as well as into the amino group, creating [C2, C6'-(13)C(2)] thiamin and [N4'-(15)N] thiamin. Magic-angle spinning (MAS) NMR spectroscopy has been employed to record the (13)C and (15)N chemical shift anisotropy (CSA) tensors for C2, C6', and N4' atoms. Our results indicate that the isotropic chemical shifts as well as the principal components of the (13)C and (15)N CSA tensors are very sensitive to the protonati

SUBMITTER: Paramasivam S 

PROVIDER: S-EPMC3227141 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature