Figure 4.

Partial modelled structures of PtmN, PtmA, PtmB and PtmG in complex with PtmI (cyan). (a) putative active site pocket of PtmN, (b) putative active site pocket of PtmA, (c) putative active site pocket of PtmB, (d) putative active site pocket of PtmG. The Ser residue in PtmI is conserved for the phosphopantetheinyl moiety attachment. The location of cofactors was determined based on superimposition of the modelled structures with the X-ray crystal structures of similar enzymes. The black dashed lines show the tunnels for phosphopantetheinyl-bound substrates. The yellow dashed line shows the distance between the conserved Ser residue of PtmI and Zn²⁺ ion.