Exploring Protein-MOF Interactions with Luminescent 2D Frameworks: Catalysis and Sensing with LMOF-601

Proteases like trypsin are typically used to efficiently fragment proteins into peptides, which is necessary for the analysis of proteins. These enzymes do have limitations however, such as instability, self-digestion, and the creation of extremely small fragments. Metal–organic frameworks have become strong artificial substitutes to overcome these limits. With their multifunctionality, tunable pores, and crystallinity, luminescent MOFs in particular, have attracted more attention as biomolecule catalysts and selective sensors. This work focuses on the synthesis and development of a luminescent two-dimensional Zirconium-based Metal-Organic Framework, LMOF-601, as a heterogeneous catalyst for protein hydrolysis and also as a system to gain insight into protein–MOF interactions. LMOF-601 was prepared according to a solvothermal synthesis, and the material was further characterized using different techniques. Cytochrome c cleavage monitored by SDS-PAGE and Gly-Gly hydrolysis under nearly physiological conditions were used to validate its catalytic activity. Additionally, the fact that structural integrity was maintained throughout shows that LMOF-601 is a stable and potentially reusable heterogeneous catalyst. The unique feature of this work is its use of LMOF-601 inherent luminescence to investigate protein interactions. Depending on the used protein, systematic fluorescence quenching experiments showed different responses, which allowed them to be grouped based on features derived from the sequence. This study provides insight on how proteins interact with functional porous materials by connecting fluorescence modulation to protein characteristics. The LMOF-601 fluorescence response is a potent tool for studying protein-MOF interactions, offers insightful information about how proteins behave when functional porous materials are present, and may help creating MOF materials that function as artificial proteases and innovative protein detection techniques.