Figure 4

Structural details of key FAS enzymatic domains. For each key enzymatic domain (KS—ketoacyl synthase, AT—acetyl transferase, ER—enoyl reductase, MPT—malonyl/palmitoyl transferase), surfaces are shown for both P. pastoris FAS and S. cerevisiae FAS (PDB 6TA1²⁰), coloured according to electrostatic charge (blue—positive, red—negative). The locations of the active sites are highlighted by dashed boxes (AT/ER/MPT) or black arrows (KS). An overlay of the atomic models is also shown (P. pastoris FAS—orange, S. cerevisiae FAS—blue) with enlarged images of key active site residues (located within the solid boxes). Density for P. pastoris FAS is shown around highlighted active site residues. FMN and corresponding EM density is shown in pink. Key differences are highlighted by asterisks (Q171 in the AT domain, H749 in the ER domain, MPT subdomain arrangement).