Presumed substrate binding sites of LmTryS as derived from the model with bound ADP/Mg2+ and the Gsp analogue.
ATP is assumed to essentially occupy the position of ADP. The position of the ATP γ-phosphate is mimicked by the phosphoryl group of the Gsp analogue. The red line marks the binding site of GSH, the green line that of spermidine. The empty pocket surrounded by a magenta line can harber the glutathionyl moiety of Gsp and, together with the spermidine binding site, thus could form a Gsp binding site.