Determination of the binding specificity of the 12S subunit of the transcarboxylase by saturation transfer difference NMR

In this study we present the characterization of the interaction of biotin and methylmalonyl-CoA (MMCoA) with the carboxyltransferase subunit (12S) from the transcarboxylase (TC) from Propionibacterium shermanii. This biotin dependent multienzyme complex catalyses the transfer of carbon dioxide from methylmalonyl-CoA (MMCoA) to pyruvate. The Saturation Transfer Difference NMR (STD) technique was performed to determine the binding epitope from biotin and MMCoA to the 12S subunit. We could show by titrations during STD experiments that biotin and MMCoA bind cooperatively in one binding pocket.