fix pdb parser: need cif-category not table

src/mol-model-formats/structure/pdb/to-cif.ts

@@ -162,8 +162,8 @@ export async function pdbToMmCif(pdb: PdbFile): Promise<CifFrame> {
     }
 
     const categories = {
-        entity: entityBuilder.getEntityTable(),
-        chem_comp: componentBuilder.getChemCompTable(),
+        entity: CifCategory.ofTable('entity', entityBuilder.getEntityTable()),
+        chem_comp: CifCategory.ofTable('chem_comp', componentBuilder.getChemCompTable()),
         atom_site: CifCategory.ofFields('atom_site', getAtomSite(atomSite)),
         atom_site_anisotrop: CifCategory.ofFields('atom_site_anisotrop', getAnisotropic(anisotropic))
     } as any;