Extended Data Fig. 3: Evaluation of ions in submitted models (stereo images).

(a) Target 1 6cvm reference model Mg A2002 (gray sphere) with water ligands (orange spheres), located near the PETG ligand, with density for classic octahedral coordination. Only six of 23 submitted Target 1 models included the Mg²⁺ and all three coordinating waters. Others had either only Mg²⁺, Mg²⁺ plus one or two waters, Mg²⁺ plus waters with zero occupancy, no atoms modeled, or atoms significantly displaced. (b) Some groups placed metal ions with weak justification, as exemplified by the Na⁺ (grey sphere) shown here in model EM005_1 for Target 3.