Synthesis of [18,19,21,22-(13)C4]-labeled tautomycin as an NMR probe of protein phosphatase inhibitor.

We have accomplished the synthesis of 13C-labeled tautomycin at the C18, C19, C21, and C22 positions starting from 100% [13C]triethylphosphonoacetate for the purpose of elucidating the dynamics and conformation of the C17-C26 moiety. NMR spectroscopy of 13C-labeled tautomycin revealed strong binding with protein phosphatase type 1 and new features in the 13C NMR spectrum, such as the very small three-bond coupling constants (2J).