Fig. 2: Structural and mechanistic details of GdmF.
From: Structure and function of the geldanamycin amide synthase from Streptomyces hygroscopicus
a–d Crystal structure of ligand-free enzyme GdmF. e Macrolactam formation of progeldanamycin 2 from activated seco-progeldanamycin 1 by GdmF which corresponds to mechanistic analogy to amide formation established for NATs. a Overview of the ligand-free GdmF crystal structure at 1.4 Å resolution: α-helical bundle (magenta), β-barrel (green), interdomain region (blue), and α/β-lid (orange). Thirteen amino acids located in the interdomain region (dashed line) are not resolved in the crystal structure. b Close-up view of the active site. The catalytic triad and its surrounding hydrophobic residues are shown in stick representation. c Structural differences of the active site residues between GdmF (colored) and MlNAT1 (light gray). d Surface representation of GdmF, showing the active site cleft, and colored according to the electrostatic potential. Color code: red: negative, blue: positive, white, neutral.
