Catalytic Intermediate Crystal Structures of Cysteine Desulfurase from the Archaeon Thermococcus onnurineus NA1

Scheme 1

Simplified catalytic mechanism of CDS with the conserved Cys and Lys residues and PLP cofactor in the active site. For the catalytic residues, the corresponding residue numbers of ToCDS are labelled. The substrate channel is represented as a blue shade. Four catalytic intermediate structures of ToCDS (NAT, GD, IAA, and PSF) determined in this study are labelled in bold black letters.