Lamellar Enzyme-Metal-Organic Framework Composites Enable Catalysis on Large Substrates

Zeolitic imidazolate framework(ZIF)is a representative type of metal–organic framework that has been extensively used as a carrier in enzyme immobilization.However,thus far the immobilization studies have mainly been carried out on enzymes with small substrates(e.g.,peroxide and glucose),and the general applicability of ZIF in enzyme immobilization has not been investigated.In this study,we show that,owing to its small aperture size,the canonical sodalite ZIF[ZIF-8 or sod-Zn(mIM)_(2)(mIM=2-methylimidazolate)]cannot be used for enzymes with large substrates.Instead,we show that the lamellar,nanoflower-like ZIF[nf-Zn(mIM)_(2)]synthesized in low precursor concentrations overcomes the size limitation of sod-Zn(mIM)_(2) and is suitable for immobilization of various enzymes with large substrates.Remarkably,the lamellar ZIF can work with a thioesterase,which acts on a peptide with 11 amino acids to produce an analog of teixobactin,a superantibiotic with no antimicrobial resistance thus far.The lamellar ZIF scaffold is highly efficient in enzyme loading and significantly increases enzyme stability against disfavorable conditions,serving as a general carrier in enzyme immobilization.